Author: ceki Date: Wed Mar 4 21:05:53 2009 New Revision: 2179 Added: logback/trunk/logback-classic/src/test/input/corpus/ logback/trunk/logback-classic/src/test/input/corpus/origin_of_species.txt logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/corpus/ logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/corpus/CorpusMakerUtil.java logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/corpus/ExceptionBuilder.java logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/corpus/MessageEntry.java logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/corpus/RandomUtil.java logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/corpus/TextFileUtil.java logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/corpusTest/ logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/corpusTest/FileToWord.java logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/corpusTest/RandomUtilTest.java Removed: logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/control/RandomUtilTest.java Modified: logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/control/PackageTest.java logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/control/ScenarioRandomUtil.java Log: Started work on the corpus. Added: logback/trunk/logback-classic/src/test/input/corpus/origin_of_species.txt ============================================================================== --- (empty file) +++ logback/trunk/logback-classic/src/test/input/corpus/origin_of_species.txt Wed Mar 4 21:05:53 2009 @@ -0,0 +1,1276 @@ +Darwin, Charles, 1809-1882 + +ON THE ORIGIN OF SPECIES. + +INTRODUCTION. + +When on board H.M.S. 'Beagle,' as naturalist, I was much struck with +certain facts in the distribution of the inhabitants of South America, +and in the geological relations of the present to the past inhabitants +of that continent. These facts seemed to me to throw some light on the +origin of species--that mystery of mysteries, as it has been called by +one of our greatest philosophers. On my return home, it occurred to +me, in 1837, that something might perhaps be made out on this question +by patiently accumulating and reflecting on all sorts of facts which +could possibly have any bearing on it. After five years' work I +allowed myself to speculate on the subject, and drew up some short +notes; these I enlarged in 1844 into a sketch of the conclusions, +which then seemed to me probable: from that period to the present day +I have steadily pursued the same object. I hope that I may be excused +for entering on these personal details, as I give them to show that I +have not been hasty in coming to a decision. + +My work is now nearly finished; but as it will take me two or three +more years to complete it, and as my health is far from strong, I have +been urged to publish this Abstract. I have more especially been +induced to do this, as Mr. Wallace, who is now studying the natural +history of the Malay archipelago, has arrived at almost exactly the +same general conclusions that I have on the origin of species. Last +year he sent to me a memoir on this subject, with a request that I +would forward it to Sir Charles Lyell, who sent it to the Linnean +Society, and it is published in the third volume of the Journal of +that Society. Sir C. Lyell and Dr. Hooker, who both knew of my +work--the latter having read my sketch of 1844--honoured me by +thinking it advisable to publish, with Mr. Wallace's excellent memoir, +some brief extracts from my manuscripts. + +This Abstract, which I now publish, must necessarily be imperfect. I +cannot here give references and authorities for my several statements; +and I must trust to the reader reposing some confidence in my +accuracy. No doubt errors will have crept in, though I hope I have +always been cautious in trusting to good authorities alone. I can here +give only the general conclusions at which I have arrived, with a few +facts in illustration, but which, I hope, in most cases will suffice. +No one can feel more sensible than I do of the necessity of hereafter +publishing in detail all the facts, with references, on which my +conclusions have been grounded; and I hope in a future work to do +this. For I am well aware that scarcely a single point is discussed in +this volume on which facts cannot be adduced, often apparently leading +to conclusions directly opposite to those at which I have arrived. A +fair result can be obtained only by fully stating and balancing the +facts and arguments on both sides of each question; and this cannot +possibly be here done. + +I much regret that want of space prevents my having the satisfaction +of acknowledging the generous assistance which I have received from +very many naturalists, some of them personally unknown to me. I +cannot, however, let this opportunity pass without expressing my deep +obligations to Dr. Hooker, who for the last fifteen years has aided me +in every possible way by his large stores of knowledge and his +excellent judgment. + +In considering the Origin of Species, it is quite conceivable that a +naturalist, reflecting on the mutual affinities of organic beings, on +their embryological relations, their geographical distribution, +geological succession, and other such facts, might come to the +conclusion that each species had not been independently created, but +had descended, like varieties, from other species. Nevertheless, such +a conclusion, even if well founded, would be unsatisfactory, until it +could be shown how the innumerable species inhabiting this world have +been modified, so as to acquire that perfection of structure and +coadaptation which most justly excites our admiration. Naturalists +continually refer to external conditions, such as climate, food, etc., +as the only possible cause of variation. In one very limited sense, as +we shall hereafter see, this may be true; but it is preposterous to +attribute to mere external conditions, the structure, for instance, of +the woodpecker, with its feet, tail, beak, and tongue, so admirably +adapted to catch insects under the bark of trees. In the case of the +misseltoe, which draws its nourishment from certain trees, which has +seeds that must be transported by certain birds, and which has flowers +with separate sexes absolutely requiring the agency of certain insects +to bring pollen from one flower to the other, it is equally +preposterous to account for the structure of this parasite, with its +relations to several distinct organic beings, by the effects of +external conditions, or of habit, or of the volition of the plant +itself. + +The author of the 'Vestiges of Creation' would, I presume, say that, +after a certain unknown number of generations, some bird had given +birth to a woodpecker, and some plant to the misseltoe, and that these +had been produced perfect as we now see them; but this assumption +seems to me to be no explanation, for it leaves the case of the +coadaptations of organic beings to each other and to their physical +conditions of life, untouched and unexplained. + +It is, therefore, of the highest importance to gain a clear insight +into the means of modification and coadaptation. At the commencement +of my observations it seemed to me probable that a careful study of +domesticated animals and of cultivated plants would offer the best +chance of making out this obscure problem. Nor have I been +disappointed; in this and in all other perplexing cases I have +invariably found that our knowledge, imperfect though it be, of +variation under domestication, afforded the best and safest clue. I +may venture to express my conviction of the high value of such +studies, although they have been very commonly neglected by +naturalists. + +From these considerations, I shall devote the first chapter of this +Abstract to Variation under Domestication. We shall thus see that a +large amount of hereditary modification is at least possible, and, +what is equally or more important, we shall see how great is the power +of man in accumulating by his Selection successive slight variations. +I will then pass on to the variability of species in a state of +nature; but I shall, unfortunately, be compelled to treat this subject +far too briefly, as it can be treated properly only by giving long +catalogues of facts. We shall, however, be enabled to discuss what +circumstances are most favourable to variation. In the next chapter +the Struggle for Existence amongst all organic beings throughout the +world, which inevitably follows from their high geometrical powers of +increase, will be treated of. This is the doctrine of Malthus, applied +to the whole animal and vegetable kingdoms. As many more individuals +of each species are born than can possibly survive; and as, +consequently, there is a frequently recurring struggle for existence, +it follows that any being, if it vary however slightly in any manner +profitable to itself, under the complex and sometimes varying +conditions of life, will have a better chance of surviving, and thus +be NATURALLY SELECTED. From the strong principle of inheritance, any +selected variety will tend to propagate its new and modified form. + +This fundamental subject of Natural Selection will be treated at some +length in the fourth chapter; and we shall then see how Natural +Selection almost inevitably causes much Extinction of the less +improved forms of life and induces what I have called Divergence of +Character. In the next chapter I shall discuss the complex and little +known laws of variation and of correlation of growth. In the four +succeeding chapters, the most apparent and gravest difficulties on the +theory will be given: namely, first, the difficulties of transitions, +or in understanding how a simple being or a simple organ can be +changed and perfected into a highly developed being or elaborately +constructed organ; secondly the subject of Instinct, or the mental +powers of animals, thirdly, Hybridism, or the infertility of species +and the fertility of varieties when intercrossed; and fourthly, the +imperfection of the Geological Record. In the next chapter I shall +consider the geological succession of organic beings throughout time; +in the eleventh and twelfth, their geographical distribution +throughout space; in the thirteenth, their classification or mutual +affinities, both when mature and in an embryonic condition. In the +last chapter I shall give a brief recapitulation of the whole work, +and a few concluding remarks. + +No one ought to feel surprise at much remaining as yet unexplained in +regard to the origin of species and varieties, if he makes due +allowance for our profound ignorance in regard to the mutual relations +of all the beings which live around us. Who can explain why one +species ranges widely and is very numerous, and why another allied +species has a narrow range and is rare? Yet these relations are of the +highest importance, for they determine the present welfare, and, as I +believe, the future success and modification of every inhabitant of +this world. Still less do we know of the mutual relations of the +innumerable inhabitants of the world during the many past geological +epochs in its history. Although much remains obscure, and will long +remain obscure, I can entertain no doubt, after the most deliberate +study and dispassionate judgment of which I am capable, that the view +which most naturalists entertain, and which I formerly +entertained--namely, that each species has been independently +created--is erroneous. I am fully convinced that species are not +immutable; but that those belonging to what are called the same genera +are lineal descendants of some other and generally extinct species, in +the same manner as the acknowledged varieties of any one species are +the descendants of that species. Furthermore, I am convinced that +Natural Selection has been the main but not exclusive means of +modification. + +CHAPTER 1. VARIATION UNDER DOMESTICATION. + +Causes of Variability. +Effects of Habit. +Correlation of Growth. +Inheritance. +Character of Domestic Varieties. +Difficulty of distinguishing between Varieties and Species. +Origin of Domestic Varieties from one or more Species. +Domestic Pigeons, their Differences and Origin. +Principle of Selection anciently followed, its Effects. +Methodical and Unconscious Selection. +Unknown Origin of our Domestic Productions. +Circumstances favourable to Man's power of Selection. + +When we look to the individuals of the same variety or sub-variety of +our older cultivated plants and animals, one of the first points which +strikes us, is, that they generally differ much more from each other, +than do the individuals of any one species or variety in a state of +nature. When we reflect on the vast diversity of the plants and +animals which have been cultivated, and which have varied during all +ages under the most different climates and treatment, I think we are +driven to conclude that this greater variability is simply due to our +domestic productions having been raised under conditions of life not +so uniform as, and somewhat different from, those to which the +parent-species have been exposed under nature. There is, also, I +think, some probability in the view propounded by Andrew Knight, that +this variability may be partly connected with excess of food. It seems +pretty clear that organic beings must be exposed during several +generations to the new conditions of life to cause any appreciable +amount of variation; and that when the organisation has once begun to +vary, it generally continues to vary for many generations. No case is +on record of a variable being ceasing to be variable under +cultivation. Our oldest cultivated plants, such as wheat, still often +yield new varieties: our oldest domesticated animals are still capable +of rapid improvement or modification. + +It has been disputed at what period of life the causes of variability, +whatever they may be, generally act; whether during the early or late +period of development of the embryo, or at the instant of conception. +Geoffroy St. Hilaire's experiments show that unnatural treatment of +the embryo causes monstrosities; and monstrosities cannot be separated +by any clear line of distinction from mere variations. But I am +strongly inclined to suspect that the most frequent cause of +variability may be attributed to the male and female reproductive +elements having been affected prior to the act of conception. Several +reasons make me believe in this; but the chief one is the remarkable +effect which confinement or cultivation has on the functions of the +reproductive system; this system appearing to be far more susceptible +than any other part of the organisation, to the action of any change +in the conditions of life. Nothing is more easy than to tame an +animal, and few things more difficult than to get it to breed freely +under confinement, even in the many cases when the male and female +unite. How many animals there are which will not breed, though living +long under not very close confinement in their native country! This is +generally attributed to vitiated instincts; but how many cultivated +plants display the utmost vigour, and yet rarely or never seed! In +some few such cases it has been found out that very trifling changes, +such as a little more or less water at some particular period of +growth, will determine whether or not the plant sets a seed. I cannot +here enter on the copious details which I have collected on this +curious subject; but to show how singular the laws are which determine +the reproduction of animals under confinement, I may just mention that +carnivorous animals, even from the tropics, breed in this country +pretty freely under confinement, with the exception of the +plantigrades or bear family; whereas, carnivorous birds, with the +rarest exceptions, hardly ever lay fertile eggs. Many exotic plants +have pollen utterly worthless, in the same exact condition as in the +most sterile hybrids. When, on the one hand, we see domesticated +animals and plants, though often weak and sickly, yet breeding quite +freely under confinement; and when, on the other hand, we see +individuals, though taken young from a state of nature, perfectly +tamed, long-lived, and healthy (of which I could give numerous +instances), yet having their reproductive system so seriously affected +by unperceived causes as to fail in acting, we need not be surprised +at this system, when it does act under confinement, acting not quite +regularly, and producing offspring not perfectly like their parents or +variable. + +Sterility has been said to be the bane of horticulture; but on this +view we owe variability to the same cause which produces sterility; +and variability is the source of all the choicest productions of the +garden. I may add, that as some organisms will breed most freely under +the most unnatural conditions (for instance, the rabbit and ferret +kept in hutches), showing that their reproductive system has not been +thus affected; so will some animals and plants withstand domestication +or cultivation, and vary very slightly--perhaps hardly more than in a +state of nature. + +A long list could easily be given of "sporting plants;" by this term +gardeners mean a single bud or offset, which suddenly assumes a new +and sometimes very different character from that of the rest of the +plant. Such buds can be propagated by grafting, etc., and sometimes by +seed. These "sports" are extremely rare under nature, but far from +rare under cultivation; and in this case we see that the treatment of +the parent has affected a bud or offset, and not the ovules or pollen. +But it is the opinion of most physiologists that there is no essential +difference between a bud and an ovule in their earliest stages of +formation; so that, in fact, "sports" support my view, that +variability may be largely attributed to the ovules or pollen, or to +both, having been affected by the treatment of the parent prior to the +act of conception. These cases anyhow show that variation is not +necessarily connected, as some authors have supposed, with the act of +generation. + +Seedlings from the same fruit, and the young of the same litter, +sometimes differ considerably from each other, though both the young +and the parents, as Muller has remarked, have apparently been exposed +to exactly the same conditions of life; and this shows how unimportant +the direct effects of the conditions of life are in comparison with +the laws of reproduction, and of growth, and of inheritance; for had +the action of the conditions been direct, if any of the young had +varied, all would probably have varied in the same manner. To judge +how much, in the case of any variation, we should attribute to the +direct action of heat, moisture, light, food, etc., is most difficult: +my impression is, that with animals such agencies have produced very +little direct effect, though apparently more in the case of plants. +Under this point of view, Mr. Buckman's recent experiments on plants +seem extremely valuable. When all or nearly all the individuals +exposed to certain conditions are affected in the same way, the change +at first appears to be directly due to such conditions; but in some +cases it can be shown that quite opposite conditions produce similar +changes of structure. Nevertheless some slight amount of change may, I +think, be attributed to the direct action of the conditions of +life--as, in some cases, increased size from amount of food, colour +from particular kinds of food and from light, and perhaps the +thickness of fur from climate. + +Habit also has a decided influence, as in the period of flowering with +plants when transported from one climate to another. In animals it has +a more marked effect; for instance, I find in the domestic duck that +the bones of the wing weigh less and the bones of the leg more, in +proportion to the whole skeleton, than do the same bones in the +wild-duck; and I presume that this change may be safely attributed to +the domestic duck flying much less, and walking more, than its wild +parent. The great and inherited development of the udders in cows and +goats in countries where they are habitually milked, in comparison +with the state of these organs in other countries, is another instance +of the effect of use. Not a single domestic animal can be named which +has not in some country drooping ears; and the view suggested by some +authors, that the drooping is due to the disuse of the muscles of the +ear, from the animals not being much alarmed by danger, seems +probable. + +There are many laws regulating variation, some few of which can be +dimly seen, and will be hereafter briefly mentioned. I will here only +allude to what may be called correlation of growth. Any change in the +embryo or larva will almost certainly entail changes in the mature +animal. In monstrosities, the correlations between quite distinct +parts are very curious; and many instances are given in Isidore +Geoffroy St. Hilaire's great work on this subject. Breeders believe +that long limbs are almost always accompanied by an elongated head. +Some instances of correlation are quite whimsical; thus cats with blue +eyes are invariably deaf; colour and constitutional peculiarities go +together, of which many remarkable cases could be given amongst +animals and plants. From the facts collected by Heusinger, it appears +that white sheep and pigs are differently affected from coloured +individuals by certain vegetable poisons. Hairless dogs have imperfect +teeth; long-haired and coarse-haired animals are apt to have, as is +asserted, long or many horns; pigeons with feathered feet have skin +between their outer toes; pigeons with short beaks have small feet, +and those with long beaks large feet. Hence, if man goes on selecting, +and thus augmenting, any peculiarity, he will almost certainly +unconsciously modify other parts of the structure, owing to the +mysterious laws of the correlation of growth. + +The result of the various, quite unknown, or dimly seen laws of +variation is infinitely complex and diversified. It is well worth +while carefully to study the several treatises published on some of +our old cultivated plants, as on the hyacinth, potato, even the +dahlia, etc.; and it is really surprising to note the endless points +in structure and constitution in which the varieties and sub-varieties +differ slightly from each other. The whole organisation seems to have +become plastic, and tends to depart in some small degree from that of +the parental type. + +Any variation which is not inherited is unimportant for us. But the +number and diversity of inheritable deviations of structure, both +those of slight and those of considerable physiological importance, is +endless. Dr. Prosper Lucas's treatise, in two large volumes, is the +fullest and the best on this subject. No breeder doubts how strong is +the tendency to inheritance: like produces like is his fundamental +belief: doubts have been thrown on this principle by theoretical +writers alone. When a deviation appears not unfrequently, and we see +it in the father and child, we cannot tell whether it may not be due +to the same original cause acting on both; but when amongst +individuals, apparently exposed to the same conditions, any very rare +deviation, due to some extraordinary combination of circumstances, +appears in the parent--say, once amongst several million +individuals--and it reappears in the child, the mere doctrine of +chances almost compels us to attribute its reappearance to +inheritance. Every one must have heard of cases of albinism, prickly +skin, hairy bodies, etc., appearing in several members of the same +family. If strange and rare deviations of structure are truly +inherited, less strange and commoner deviations may be freely admitted +to be inheritable. Perhaps the correct way of viewing the whole +subject, would be, to look at the inheritance of every character +whatever as the rule, and non-inheritance as the anomaly. + +The laws governing inheritance are quite unknown; no one can say why +the same peculiarity in different individuals of the same species, and +in individuals of different species, is sometimes inherited and +sometimes not so; why the child often reverts in certain characters to +its grandfather or grandmother or other much more remote ancestor; why +a peculiarity is often transmitted from one sex to both sexes or to +one sex alone, more commonly but not exclusively to the like sex. It +is a fact of some little importance to us, that peculiarities +appearing in the males of our domestic breeds are often transmitted +either exclusively, or in a much greater degree, to males alone. A +much more important rule, which I think may be trusted, is that, at +whatever period of life a peculiarity first appears, it tends to +appear in the offspring at a corresponding age, though sometimes +earlier. In many cases this could not be otherwise: thus the inherited +peculiarities in the horns of cattle could appear only in the +offspring when nearly mature; peculiarities in the silkworm are known +to appear at the corresponding caterpillar or cocoon stage. But +hereditary diseases and some other facts make me believe that the rule +has a wider extension, and that when there is no apparent reason why a +peculiarity should appear at any particular age, yet that it does tend +to appear in the offspring at the same period at which it first +appeared in the parent. I believe this rule to be of the highest +importance in explaining the laws of embryology. These remarks are of +course confined to the first APPEARANCE of the peculiarity, and not to +its primary cause, which may have acted on the ovules or male element; +in nearly the same manner as in the crossed offspring from a +short-horned cow by a long-horned bull, the greater length of horn, +though appearing late in life, is clearly due to the male element. + +Having alluded to the subject of reversion, I may here refer to a +statement often made by naturalists--namely, that our domestic +varieties, when run wild, gradually but certainly revert in character +to their aboriginal stocks. Hence it has been argued that no +deductions can be drawn from domestic races to species in a state of +nature. I have in vain endeavoured to discover on what decisive facts +the above statement has so often and so boldly been made. There would +be great difficulty in proving its truth: we may safely conclude that +very many of the most strongly-marked domestic varieties could not +possibly live in a wild state. In many cases we do not know what the +aboriginal stock was, and so could not tell whether or not nearly +perfect reversion had ensued. It would be quite necessary, in order to +prevent the effects of intercrossing, that only a single variety +should be turned loose in its new home. Nevertheless, as our varieties +certainly do occasionally revert in some of their characters to +ancestral forms, it seems to me not improbable, that if we could +succeed in naturalising, or were to cultivate, during many +generations, the several races, for instance, of the cabbage, in very +poor soil (in which case, however, some effect would have to be +attributed to the direct action of the poor soil), that they would to +a large extent, or even wholly, revert to the wild aboriginal stock. +Whether or not the experiment would succeed, is not of great +importance for our line of argument; for by the experiment itself the +conditions of life are changed. If it could be shown that our domestic +varieties manifested a strong tendency to reversion,--that is, to lose +their acquired characters, whilst kept under unchanged conditions, and +whilst kept in a considerable body, so that free intercrossing might +check, by blending together, any slight deviations of structure, in +such case, I grant that we could deduce nothing from domestic +varieties in regard to species. But there is not a shadow of evidence +in favour of this view: to assert that we could not breed our cart and +race-horses, long and short-horned cattle, and poultry of various +breeds, and esculent vegetables, for an almost infinite number of +generations, would be opposed to all experience. I may add, that when +under nature the conditions of life do change, variations and +reversions of character probably do occur; but natural selection, as +will hereafter be explained, will determine how far the new characters +thus arising shall be preserved. + +When we look to the hereditary varieties or races of our domestic +animals and plants, and compare them with species closely allied +together, we generally perceive in each domestic race, as already +remarked, less uniformity of character than in true species. Domestic +races of the same species, also, often have a somewhat monstrous +character; by which I mean, that, although differing from each other, +and from the other species of the same genus, in several trifling +respects, they often differ in an extreme degree in some one part, +both when compared one with another, and more especially when compared +with all the species in nature to which they are nearest allied. With +these exceptions (and with that of the perfect fertility of varieties +when crossed,--a subject hereafter to be discussed), domestic races of +the same species differ from each other in the same manner as, only in +most cases in a lesser degree than, do closely-allied species of the +same genus in a state of nature. I think this must be admitted, when +we find that there are hardly any domestic races, either amongst +animals or plants, which have not been ranked by some competent judges +as mere varieties, and by other competent judges as the descendants of +aboriginally distinct species. If any marked distinction existed +between domestic races and species, this source of doubt could not so +perpetually recur. It has often been stated that domestic races do not +differ from each other in characters of generic value. I think it +could be shown that this statement is hardly correct; but naturalists +differ most widely in determining what characters are of generic +value; all such valuations being at present empirical. Moreover, on +the view of the origin of genera which I shall presently give, we have +no right to expect often to meet with generic differences in our +domesticated productions. + +When we attempt to estimate the amount of structural difference +between the domestic races of the same species, we are soon involved +in doubt, from not knowing whether they have descended from one or +several parent-species. This point, if it could be cleared up, would +be interesting; if, for instance, it could be shown that the +greyhound, bloodhound, terrier, spaniel, and bull-dog, which we all +know propagate their kind so truly, were the offspring of any single +species, then such facts would have great weight in making us doubt +about the immutability of the many very closely allied and natural +species--for instance, of the many foxes--inhabiting different +quarters of the world. I do not believe, as we shall presently see, +that all our dogs have descended from any one wild species; but, in +the case of some other domestic races, there is presumptive, or even +strong, evidence in favour of this view. + +It has often been assumed that man has chosen for domestication +animals and plants having an extraordinary inherent tendency to vary, +and likewise to withstand diverse climates. I do not dispute that +these capacities have added largely to the value of most of our +domesticated productions; but how could a savage possibly know, when +he first tamed an animal, whether it would vary in succeeding +generations, and whether it would endure other climates? Has the +little variability of the ass or guinea-fowl, or the small power of +endurance of warmth by the rein-deer, or of cold by the common camel, +prevented their domestication? I cannot doubt that if other animals +and plants, equal in number to our domesticated productions, and +belonging to equally diverse classes and countries, were taken from a +state of nature, and could be made to breed for an equal number of +generations under domestication, they would vary on an average as +largely as the parent species of our existing domesticated productions +have varied. + +In the case of most of our anciently domesticated animals and plants, +I do not think it is possible to come to any definite conclusion, +whether they have descended from one or several species. The argument +mainly relied on by those who believe in the multiple origin of our +domestic animals is, that we find in the most ancient records, more +especially on the monuments of Egypt, much diversity in the breeds; +and that some of the breeds closely resemble, perhaps are identical +with, those still existing. Even if this latter fact were found more +strictly and generally true than seems to me to be the case, what does +it show, but that some of our breeds originated there, four or five +thousand years ago? But Mr. Horner's researches have rendered it in +some degree probable that man sufficiently civilized to have +manufactured pottery existed in the valley of the Nile thirteen or +fourteen thousand years ago; and who will pretend to say how long +before these ancient periods, savages, like those of Tierra del Fuego +or Australia, who possess a semi-domestic dog, may not have existed in +Egypt? + +The whole subject must, I think, remain vague; nevertheless, I may, +without here entering on any details, state that, from geographical +and other considerations, I think it highly probable that our domestic +dogs have descended from several wild species. In regard to sheep and +goats I can form no opinion. I should think, from facts communicated +to me by Mr. Blyth, on the habits, voice, and constitution, etc., of +the humped Indian cattle, that these had descended from a different +aboriginal stock from our European cattle; and several competent +judges believe that these latter have had more than one wild parent. +With respect to horses, from reasons which I cannot give here, I am +doubtfully inclined to believe, in opposition to several authors, that +all the races have descended from one wild stock. Mr. Blyth, whose +opinion, from his large and varied stores of knowledge, I should value +more than that of almost any one, thinks that all the breeds of +poultry have proceeded from the common wild Indian fowl (Gallus +bankiva). In regard to ducks and rabbits, the breeds of which differ +considerably from each other in structure, I do not doubt that they +all have descended from the common wild duck and rabbit. + +The doctrine of the origin of our several domestic races from several +aboriginal stocks, has been carried to an absurd extreme by some +authors. They believe that every race which breeds true, let the +distinctive characters be ever so slight, has had its wild prototype. +At this rate there must have existed at least a score of species of +wild cattle, as many sheep, and several goats in Europe alone, and +several even within Great Britain. One author believes that there +formerly existed in Great Britain eleven wild species of sheep +peculiar to it! When we bear in mind that Britain has now hardly one +peculiar mammal, and France but few distinct from those of Germany and +conversely, and so with Hungary, Spain, etc., but that each of these +kingdoms possesses several peculiar breeds of cattle, sheep, etc., we +must admit that many domestic breeds have originated in Europe; for +whence could they have been derived, as these several countries do not +possess a number of peculiar species as distinct parent-stocks? So it +is in India. Even in the case of the domestic dogs of the whole world, +which I fully admit have probably descended from several wild species, +I cannot doubt that there has been an immense amount of inherited +variation. Who can believe that animals closely resembling the Italian +greyhound, the bloodhound, the bull-dog, or Blenheim spaniel, etc.--so +unlike all wild Canidae--ever existed freely in a state of nature? It +has often been loosely said that all our races of dogs have been +produced by the crossing of a few aboriginal species; but by crossing +we can get only forms in some degree intermediate between their +parents; and if we account for our several domestic races by this +process, we must admit the former existence of the most extreme forms, +as the Italian greyhound, bloodhound, bull-dog, etc., in the wild +state. Moreover, the possibility of making distinct races by crossing +has been greatly exaggerated. There can be no doubt that a race may be +modified by occasional crosses, if aided by the careful selection of +those individual mongrels, which present any desired character; but +that a race could be obtained nearly intermediate between two +extremely different races or species, I can hardly believe. Sir J. +Sebright expressly experimentised for this object, and failed. The +offspring from the first cross between two pure breeds is tolerably +and sometimes (as I have found with pigeons) extremely uniform, and +everything seems simple enough; but when these mongrels are crossed +one with another for several generations, hardly two of them will be +alike, and then the extreme difficulty, or rather utter hopelessness, +of the task becomes apparent. Certainly, a breed intermediate between +TWO VERY DISTINCT breeds could not be got without extreme care and +long-continued selection; nor can I find a single case on record of a +permanent race having been thus formed. + +ON THE BREEDS OF THE DOMESTIC PIGEON. + +Believing that it is always best to study some special group, I have, +after deliberation, taken up domestic pigeons. I have kept every breed +which I could purchase or obtain, and have been most kindly favoured +with skins from several quarters of the world, more especially by the +Honourable W. Elliot from India, and by the Honourable C. Murray from +Persia. Many treatises in different languages have been published on +pigeons, and some of them are very important, as being of considerable +antiquity. I have associated with several eminent fanciers, and have +been permitted to join two of the London Pigeon Clubs. The diversity +of the breeds is something astonishing. Compare the English carrier +and the short-faced tumbler, and see the wonderful difference in their +beaks, entailing corresponding differences in their skulls. The +carrier, more especially the male bird, is also remarkable from the +wonderful development of the carunculated skin about the head, and +this is accompanied by greatly elongated eyelids, very large external +orifices to the nostrils, and a wide gape of mouth. The short-faced +tumbler has a beak in outline almost like that of a finch; and the +common tumbler has the singular and strictly inherited habit of flying +at a great height in a compact flock, and tumbling in the air head +over heels. The runt is a bird of great size, with long, massive beak +and large feet; some of the sub-breeds of runts have very long necks, +others very long wings and tails, others singularly short tails. The +barb is allied to the carrier, but, instead of a very long beak, has a +very short and very broad one. The pouter has a much elongated body, +wings, and legs; and its enormously developed crop, which it glories +in inflating, may well excite astonishment and even laughter. The +turbit has a very short and conical beak, with a line of reversed +feathers down the breast; and it has the habit of continually +expanding slightly the upper part of the oesophagus. The Jacobin has +the feathers so much reversed along the back of the neck that they +form a hood, and it has, proportionally to its size, much elongated +wing and tail feathers. The trumpeter and laugher, as their names +express, utter a very different coo from the other breeds. The fantail +has thirty or even forty tail-feathers, instead of twelve or fourteen, +the normal number in all members of the great pigeon family; and these +feathers are kept expanded, and are carried so erect that in good +birds the head and tail touch; the oil-gland is quite aborted. Several +other less distinct breeds might have been specified. + +In the skeletons of the several breeds, the development of the bones +of the face in length and breadth and curvature differs enormously. +The shape, as well as the breadth and length of the ramus of the lower +jaw, varies in a highly remarkable manner. The number of the caudal +and sacral vertebrae vary; as does the number of the ribs, together +with their relative breadth and the presence of processes. The size +and shape of the apertures in the sternum are highly variable; so is +the degree of divergence and relative size of the two arms of the +furcula. The proportional width of the gape of mouth, the proportional +length of the eyelids, of the orifice of the nostrils, of the tongue +(not always in strict correlation with the length of beak), the size +of the crop and of the upper part of the oesophagus; the development +and abortion of the oil-gland; the number of the primary wing and +caudal feathers; the relative length of wing and tail to each other +and to the body; the relative length of leg and of the feet; the +number of scutellae on the toes, the development of skin between the +toes, are all points of structure which are variable. The period at +which the perfect plumage is acquired varies, as does the state of the +down with which the nestling birds are clothed when hatched. The shape +and size of the eggs vary. The manner of flight differs remarkably; as +does in some breeds the voice and disposition. Lastly, in certain +breeds, the males and females have come to differ to a slight degree +from each other. + +Altogether at least a score of pigeons might be chosen, which if shown +to an ornithologist, and he were told that they were wild birds, would +certainly, I think, be ranked by him as well-defined species. +Moreover, I do not believe that any ornithologist would place the +English carrier, the short-faced tumbler, the runt, the barb, pouter, +and fantail in the same genus; more especially as in each of these +breeds several truly-inherited sub-breeds, or species as he might have +called them, could be shown him. + +Great as the differences are between the breeds of pigeons, I am fully +convinced that the common opinion of naturalists is correct, namely, +that all have descended from the rock-pigeon (Columba livia), +including under this term several geographical races or sub-species, +which differ from each other in the most trifling respects. As several +of the reasons which have led me to this belief are in some degree +applicable in other cases, I will here briefly give them. If the +several breeds are not varieties, and have not proceeded from the +rock-pigeon, they must have descended from at least seven or eight +aboriginal stocks; for it is impossible to make the present domestic +breeds by the crossing of any lesser number: how, for instance, could +a pouter be produced by crossing two breeds unless one of the +parent-stocks possessed the characteristic enormous crop? The supposed +aboriginal stocks must all have been rock-pigeons, that is, not +breeding or willingly perching on trees. But besides C. livia, with +its geographical sub-species, only two or three other species of +rock-pigeons are known; and these have not any of the characters of +the domestic breeds. Hence the supposed aboriginal stocks must either +still exist in the countries where they were originally domesticated, +and yet be unknown to ornithologists; and this, considering their +size, habits, and remarkable characters, seems very improbable; or +they must have become extinct in the wild state. But birds breeding on +precipices, and good fliers, are unlikely to be exterminated; and the +common rock-pigeon, which has the same habits with the domestic +breeds, has not been exterminated even on several of the smaller +British islets, or on the shores of the Mediterranean. Hence the +supposed extermination of so many species having similar habits with +the rock-pigeon seems to me a very rash assumption. Moreover, the +several above-named domesticated breeds have been transported to all +parts of the world, and, therefore, some of them must have been +carried back again into their native country; but not one has ever +become wild or feral, though the dovecot-pigeon, which is the +rock-pigeon in a very slightly altered state, has become feral in +several places. Again, all recent experience shows that it is most +difficult to get any wild animal to breed freely under domestication; +yet on the hypothesis of the multiple origin of our pigeons, it must +be assumed that at least seven or eight species were so thoroughly +domesticated in ancient times by half-civilized man, as to be quite +prolific under confinement. + +An argument, as it seems to me, of great weight, and applicable in +several other cases, is, that the above-specified breeds, though +agreeing generally in constitution, habits, voice, colouring, and in +most parts of their structure, with the wild rock-pigeon, yet are +certainly highly abnormal in other parts of their structure: we may +look in vain throughout the whole great family of Columbidae for a +beak like that of the English carrier, or that of the short-faced +tumbler, or barb; for reversed feathers like those of the jacobin; for +a crop like that of the pouter; for tail-feathers like those of the +fantail. Hence it must be assumed not only that half-civilized man +succeeded in thoroughly domesticating several species, but that he +intentionally or by chance picked out extraordinarily abnormal +species; and further, that these very species have since all become +extinct or unknown. So many strange contingencies seem to me +improbable in the highest degree. + +Some facts in regard to the colouring of pigeons well deserve +consideration. The rock-pigeon is of a slaty-blue, and has a white +rump (the Indian sub-species, C. intermedia of Strickland, having it +bluish); the tail has a terminal dark bar, with the bases of the outer +feathers externally edged with white; the wings have two black bars; +some semi-domestic breeds and some apparently truly wild breeds have, +besides the two black bars, the wings chequered with black. These +several marks do not occur together in any other species of the whole +family. Now, in every one of the domestic breeds, taking thoroughly +well-bred birds, all the above marks, even to the white edging of the +outer tail-feathers, sometimes concur perfectly developed. Moreover, +when two birds belonging to two distinct breeds are crossed, neither +of which is blue or has any of the above-specified marks, the mongrel +offspring are very apt suddenly to acquire these characters; for +instance, I crossed some uniformly white fantails with some uniformly +black barbs, and they produced mottled brown and black birds; these I +again crossed together, and one grandchild of the pure white fantail +and pure black barb was of as beautiful a blue colour, with the white +rump, double black wing-bar, and barred and white-edged tail-feathers, +as any wild rock-pigeon! We can understand these facts, on the +well-known principle of reversion to ancestral characters, if all the +domestic breeds have descended from the rock-pigeon. But if we deny +this, we must make one of the two following highly improbable +suppositions. Either, firstly, that all the several imagined +aboriginal stocks were coloured and marked like the rock-pigeon, +although no other existing species is thus coloured and marked, so +that in each separate breed there might be a tendency to revert to the +very same colours and markings. Or, secondly, that each breed, even +the purest, has within a dozen or, at most, within a score of +generations, been crossed by the rock-pigeon: I say within a dozen or +twenty generations, for we know of no fact countenancing the belief +that the child ever reverts to some one ancestor, removed by a greater +number of generations. In a breed which has been crossed only once +with some distinct breed, the tendency to reversion to any character +derived from such cross will naturally become less and less, as in +each succeeding generation there will be less of the foreign blood; +but when there has been no cross with a distinct breed, and there is a +tendency in both parents to revert to a character, which has been lost +during some former generation, this tendency, for all that we can see +to the contrary, may be transmitted undiminished for an indefinite +number of generations. These two distinct cases are often confounded +in treatises on inheritance. + +Lastly, the hybrids or mongrels from between all the domestic breeds +of pigeons are perfectly fertile. I can state this from my own +observations, purposely made on the most distinct breeds. Now, it is +difficult, perhaps impossible, to bring forward one case of the hybrid +offspring of two animals CLEARLY DISTINCT being themselves perfectly +fertile. Some authors believe that long-continued domestication +eliminates this strong tendency to sterility: from the history of the +dog I think there is some probability in this hypothesis, if applied +to species closely related together, though it is unsupported by a +single experiment. But to extend the hypothesis so far as to suppose +that species, aboriginally as distinct as carriers, tumblers, pouters, +and fantails now are, should yield offspring perfectly fertile, inter +se, seems to me rash in the extreme. + +From these several reasons, namely, the improbability of man having +formerly got seven or eight supposed species of pigeons to breed +freely under domestication; these supposed species being quite unknown +in a wild state, and their becoming nowhere feral; these species +having very abnormal characters in certain respects, as compared with +all other Columbidae, though so like in most other respects to the +rock-pigeon; the blue colour and various marks occasionally appearing +in all the breeds, both when kept pure and when crossed; the mongrel +offspring being perfectly fertile;--from these several reasons, taken +together, I can feel no doubt that all our domestic breeds have +descended from the Columba livia with its geographical sub-species. + +In favour of this view, I may add, firstly, that C. livia, or the +rock-pigeon, has been found capable of domestication in Europe and in +India; and that it agrees in habits and in a great number of points of +structure with all the domestic breeds. Secondly, although an English +carrier or short-faced tumbler differs immensely in certain characters +from the rock-pigeon, yet by comparing the several sub-breeds of these +breeds, more especially those brought from distant countries, we can +make an almost perfect series between the extremes of structure. +Thirdly, those characters which are mainly distinctive of each breed, +for instance the wattle and length of beak of the carrier, the +shortness of that of the tumbler, and the number of tail-feathers in +the fantail, are in each breed eminently variable; and the explanation +of this fact will be obvious when we come to treat of selection. +Fourthly, pigeons have been watched, and tended with the utmost care, +and loved by many people. They have been domesticated for thousands of +years in several quarters of the world; the earliest known record of +pigeons is in the fifth Aegyptian dynasty, about 3000 B.C., as was +pointed out to me by Professor Lepsius; but Mr. Birch informs me that +pigeons are given in a bill of fare in the previous dynasty. In the +time of the Romans, as we hear from Pliny, immense prices were given +for pigeons; "nay, they are come to this pass, that they can reckon up +their pedigree and race." Pigeons were much valued by Akber Khan in +India, about the year 1600; never less than 20,000 pigeons were taken +with the court. "The monarchs of Iran and Turan sent him some very +rare birds;" and, continues the courtly historian, "His Majesty by +crossing the breeds, which method was never practised before, has +improved them astonishingly." About this same period the Dutch were as +eager about pigeons as were the old Romans. The paramount importance +of these considerations in explaining the immense amount of variation +which pigeons have undergone, will be obvious when we treat of +Selection. We shall then, also, see how it is that the breeds so often +have a somewhat monstrous character. It is also a most favourable +circumstance for the production of distinct breeds, that male and +female pigeons can be easily mated for life; and thus different breeds +can be kept together in the same aviary. + +I have discussed the probable origin of domestic pigeons at some, yet +quite insufficient, length; because when I first kept pigeons and +watched the several kinds, knowing well how true they bred, I felt +fully as much difficulty in believing that they could ever have +descended from a common parent, as any naturalist could in coming to a +similar conclusion in regard to the many species of finches, or other +large groups of birds, in nature. One circumstance has struck me much; +namely, that all the breeders of the various domestic animals and the +cultivators of plants, with whom I have ever conversed, or whose +treatises I have read, are firmly convinced that the several breeds to +which each has attended, are descended from so many aboriginally +distinct species. Ask, as I have asked, a celebrated raiser of +Hereford cattle, whether his cattle might not have descended from long +horns, and he will laugh you to scorn. I have never met a pigeon, or +poultry, or duck, or rabbit fancier, who was not fully convinced that +each main breed was descended from a distinct species. Van Mons, in +his treatise on pears and apples, shows how utterly he disbelieves +that the several sorts, for instance a Ribston-pippin or Codlin-apple, +could ever have proceeded from the seeds of the same tree. Innumerable +other examples could be given. The explanation, I think, is simple: +from long-continued study they are strongly impressed with the +differences between the several races; and though they well know that +each race varies slightly, for they win their prizes by selecting such +slight differences, yet they ignore all general arguments, and refuse +to sum up in their minds slight differences accumulated during many +successive generations. May not those naturalists who, knowing far +less of the laws of inheritance than does the breeder, and knowing no +more than he does of the intermediate links in the long lines of +descent, yet admit that many of our domestic races have descended from +the same parents--may they not learn a lesson of caution, when they +deride the idea of species in a state of nature being lineal +descendants of other species? + +SELECTION. + +Let us now briefly consider the steps by which domestic races have +been produced, either from one or from several allied species. Some +little effect may, perhaps, be attributed to the direct action of the +external conditions of life, and some little to habit; but he would be +a bold man who would account by such agencies for the differences of a +dray and race horse, a greyhound and bloodhound, a carrier and tumbler +pigeon. One of the most remarkable features in our domesticated races +is that we see in them adaptation, not indeed to the animal's or +plant's own good, but to man's use or fancy. Some variations useful to +him have probably arisen suddenly, or by one step; many botanists, for +instance, believe that the fuller's teazle, with its hooks, which +cannot be rivalled by any mechanical contrivance, is only a variety of +the wild Dipsacus; and this amount of change may have suddenly arisen +in a seedling. So it has probably been with the turnspit dog; and this +is known to have been the case with the ancon sheep. But when we +compare the dray-horse and race-horse, the dromedary and camel, the +various breeds of sheep fitted either for cultivated land or mountain +pasture, with the wool of one breed good for one purpose, and that of +another breed for another purpose; when we compare the many breeds of +dogs, each good for man in very different ways; when we compare the +game-cock, so pertinacious in battle, with other breeds so little +quarrelsome, with "everlasting layers" which never desire to sit, and +with the bantam so small and elegant; when we compare the host of +agricultural, culinary, orchard, and flower-garden races of plants, +most useful to man at different seasons and for different purposes, or +so beautiful in his eyes, we must, I think, look further than to mere +variability. We cannot suppose that all the breeds were suddenly +produced as perfect and as useful as we now see them; indeed, in +several cases, we know that this has not been their history. The key +is man's power of accumulative selection: nature gives successive +variations; man adds them up in certain directions useful to him. In +this sense he may be said to make for himself useful breeds. + +The great power of this principle of selection is not hypothetical. It +is certain that several of our eminent breeders have, even within a +single lifetime, modified to a large extent some breeds of cattle and +sheep. In order fully to realise what they have done, it is almost +necessary to read several of the many treatises devoted to this +subject, and to inspect the animals. Breeders habitually speak of an +animal's organisation as something quite plastic, which they can model +almost as they please. If I had space I could quote numerous passages +to this effect from highly competent authorities. Youatt, who was +probably better acquainted with the works of agriculturalists than +almost any other individual, and who was himself a very good judge of +an animal, speaks of the principle of selection as "that which enables +the agriculturist, not only to modify the character of his flock, but +to change it altogether. It is the magician's wand, by means of which +he may summon into life whatever form and mould he pleases." Lord +Somerville, speaking of what breeders have done for sheep, says:--"It +would seem as if they had chalked out upon a wall a form perfect in +itself, and then had given it existence." That most skilful breeder, +Sir John Sebright, used to say, with respect to pigeons, that "he +would produce any given feather in three years, but it would take him +six years to obtain head and beak." In Saxony the importance of the +principle of selection in regard to merino sheep is so fully +recognised, that men follow it as a trade: the sheep are placed on a +table and are studied, like a picture by a connoisseur; this is done +three times at intervals of months, and the sheep are each time marked +and classed, so that the very best may ultimately be selected for +breeding. + +What English breeders have actually effected is proved by the enormous +prices given for animals with a good pedigree; and these have now been +exported to almost every quarter of the world. The improvement is by +no means generally due to crossing different breeds; all the best +breeders are strongly opposed to this practice, except sometimes +amongst closely allied sub-breeds. And when a cross has been made, the +closest selection is far more indispensable even than in ordinary +cases. If selection consisted merely in separating some very distinct +variety, and breeding from it, the principle would be so obvious as +hardly to be worth notice; but its importance consists in the great +effect produced by the accumulation in one direction, during +successive generations, of differences absolutely inappreciable by an +uneducated eye--differences which I for one have vainly attempted to +appreciate. Not one man in a thousand has accuracy of eye and judgment +sufficient to become an eminent breeder. If gifted with these +qualities, and he studies his subject for years, and devotes his +lifetime to it with indomitable perseverance, he will succeed, and may +make great improvements; if he wants any of these qualities, he will +assuredly fail. Few would readily believe in the natural capacity and +years of practice requisite to become even a skilful pigeon-fancier. + +The same principles are followed by horticulturists; but the +variations are here often more abrupt. No one supposes that our +choicest productions have been produced by a single variation from the +aboriginal stock. We have proofs that this is not so in some cases, in +which exact records have been kept; thus, to give a very trifling +instance, the steadily-increasing size of the common gooseberry may be +quoted. We see an astonishing improvement in many florists' flowers, +when the flowers of the present day are compared with drawings made +only twenty or thirty years ago. When a race of plants is once pretty +well established, the seed-raisers do not pick out the best plants, +but merely go over their seed-beds, and pull up the "rogues," as they +call the plants that deviate from the proper standard. With animals +this kind of selection is, in fact, also followed; for hardly any one +is so careless as to allow his worst animals to breed. + +In regard to plants, there is another means of observing the +accumulated effects of selection--namely, by comparing the diversity +of flowers in the different varieties of the same species in the +flower-garden; the diversity of leaves, pods, or tubers, or whatever +part is valued, in the kitchen-garden, in comparison with the flowers +of the same varieties; and the diversity of fruit of the same species +in the orchard, in comparison with the leaves and flowers of the same +set of varieties. See how different the leaves of the cabbage are, and +how extremely alike the flowers; how unlike the flowers of the +heartsease are, and how alike the leaves; how much the fruit of the +different kinds of gooseberries differ in size, colour, shape, and +hairiness, and yet the flowers present very slight differences. It is +not that the varieties which differ largely in some one point do not +differ at all in other points; this is hardly ever, perhaps never, the +case. The laws of correlation of growth, the importance of which +should never be overlooked, will ensure some differences; but, as a +general rule, I cannot doubt that the continued selection of slight +variations, either in the leaves, the flowers, or the fruit, will +produce races differing from each other chiefly in these characters. + +It may be objected that the principle of selection has been reduced to +methodical practice for scarcely more than three-quarters of a +century; it has certainly been more attended to of late years, and +many treatises have been published on the subject; and the result, I +may add, has been, in a corresponding degree, rapid and important. But +it is very far from true that the principle is a modern discovery. I +could give several references to the full acknowledgment of the +importance of the principle in works of high antiquity. In rude and +barbarous periods of English history choice animals were often +imported, and laws were passed to prevent their exportation: the +destruction of horses under a certain size was ordered, and this may +be compared to the "roguing" of plants by nurserymen. The principle of +selection I find distinctly given in an ancient Chinese encyclopaedia. +Explicit rules are laid down by some of the Roman classical writers. +From passages in Genesis, it is clear that the colour of domestic +animals was at that early period attended to. Savages now sometimes +cross their dogs with wild canine animals, to improve the breed, and +they formerly did so, as is attested by passages in Pliny. The savages +in South Africa match their draught cattle by colour, as do some of +the Esquimaux their teams of dogs. Livingstone shows how much good +domestic breeds are valued by the negroes of the interior of Africa +who have not associated with Europeans. Some of these facts do not +show actual selection, but they show that the breeding of domestic +animals was carefully attended to in ancient times, and is now +attended to by the lowest savages. It would, indeed, have been a +strange fact, had attention not been paid to breeding, for the +inheritance of good and bad qualities is so obvious. + +At the present time, eminent breeders try by methodical selection, +with a distinct object in view, to make a new strain or sub-breed, +superior to anything existing in the country. But, for our purpose, a +kind of Selection, which may be called Unconscious, and which results +from every one trying to possess and breed from the best individual +animals, is more important. Thus, a man who intends keeping pointers +naturally tries to get as good dogs as he can, and afterwards breeds +from his own best dogs, but he has no wish or expectation of +permanently altering the breed. Nevertheless I cannot doubt that this +process, continued during centuries, would improve and modify any +breed, in the same way as Bakewell, Collins, etc., by this very same +process, only carried on more methodically, did greatly modify, even +during their own lifetimes, the forms and qualities of their cattle. +Slow and insensible changes of this kind could never be recognised +unless actual measurements or careful drawings of the breeds in +question had been made long ago, which might serve for comparison. In +some cases, however, unchanged or but little changed individuals of +the same breed may be found in less civilised districts, where the +breed has been less improved. There is reason to believe that King +Charles's spaniel has been unconsciously modified to a large extent +since the time of that monarch. Some highly competent authorities are +convinced that the setter is directly derived from the spaniel, and +has probably been slowly altered from it. It is known that the English +pointer has been greatly changed within the last century, and in this +case the change has, it is believed, been chiefly effected by crosses +with the fox-hound; but what concerns us is, that the change has been +effected unconsciously and gradually, and yet so effectually, that, +though the old Spanish pointer certainly came from Spain, Mr. Borrow +has not seen, as I am informed by him, any native dog in Spain like +our pointer. + +By a similar process of selection, and by careful training, the whole +body of English racehorses have come to surpass in fleetness and size +the parent Arab stock, so that the latter, by the regulations for the +Goodwood Races, are favoured in the weights they carry. Lord Spencer +and others have shown how the cattle of England have increased in +weight and in early maturity, compared with the stock formerly kept in +this country. By comparing the accounts given in old pigeon treatises +of carriers and tumblers with these breeds as now existing in Britain, +India, and Persia, we can, I think, clearly trace the stages through +which they have insensibly passed, and come to differ so greatly from +the rock-pigeon. + +Youatt gives an excellent illustration of the effects of a course of +selection, which may be considered as unconsciously followed, in so +far that the breeders could never have expected or even have wished to +have produced the result which ensued--namely, the production of two +distinct strains. The two flocks of Leicester sheep kept by Mr. +Buckley and Mr. Burgess, as Mr. Youatt remarks, "have been purely bred +from the original stock of Mr. Bakewell for upwards of fifty years. +There is not a suspicion existing in the mind of any one at all +acquainted with the subject that the owner of either of them has +deviated in any one instance from the pure blood of Mr. Bakewell's +flock, and yet the difference between the sheep possessed by these two +gentlemen is so great that they have the appearance of being quite +different varieties." + +If there exist savages so barbarous as never to think of the inherited +character of the offspring of their domestic animals, yet any one +animal particularly useful to them, for any special purpose, would be +carefully preserved during famines and other accidents, to which +savages are so liable, and such choice animals would thus generally +leave more offspring than the inferior ones; so that in this case +there would be a kind of unconscious selection going on. We see the +value set on animals even by the barbarians of Tierra del Fuego, by +their killing and devouring their old women, in times of dearth, as of +less value than their dogs. + +In plants the same gradual process of improvement, through the +occasional preservation of the best individuals, whether or not +sufficiently distinct to be ranked at their first appearance as +distinct varieties, and whether or not two or more species or races +have become blended together by crossing, may plainly be recognised in +the increased size and beauty which we now see in the varieties of the +heartsease, rose, pelargonium, dahlia, and other plants, when compared +with the older varieties or with their parent-stocks. No one would +ever expect to get a first-rate heartsease or dahlia from the seed of +a wild plant. No one would expect to raise a first-rate melting pear +from the seed of a wild pear, though he might succeed from a poor +seedling growing wild, if it had come from a garden-stock. The pear, +though cultivated in classical times, appears, from Pliny's +description, to have been a fruit of very inferior quality. I have +seen great surprise expressed in horticultural works at the wonderful +skill of gardeners, in having produced such splendid results from such +poor materials; but the art, I cannot doubt, has been simple, and, as +far as the final result is concerned, has been followed almost +unconsciously. It has consisted in always cultivating the best known +variety, sowing its seeds, and, when a slightly better variety has +chanced to appear, selecting it, and so onwards. But the gardeners of +the classical period, who cultivated the best pear they could procure, +never thought what splendid fruit we should eat; though we owe our +excellent fruit, in some small degree, to their having naturally +chosen and preserved the best varieties they could anywhere find. + +A large amount of change in our cultivated plants, thus slowly and +unconsciously accumulated, explains, as I believe, the well-known +fact, that in a vast number of cases we cannot recognise, and +therefore do not know, the wild parent-stocks of the plants which have +been longest cultivated in our flower and kitchen gardens. If it has +taken centuries or thousands of years to improve or modify most of our +plants up to their present standard of usefulness to man, we can +understand how it is that neither Australia, the Cape of Good Hope, +nor any other region inhabited by quite uncivilised man, has afforded +us a single plant worth culture. It is not that these countries, so +rich in species, do not by a strange chance possess the aboriginal +stocks of any useful plants, but that the native plants have not been +improved by continued selection up to a standard of perfection +comparable with that given to the plants in countries anciently +civilised. + +In regard to the domestic animals kept by uncivilised man, it should +not be overlooked that they almost always have to struggle for their +own food, at least during certain seasons. And in two countries very +differently circumstanced, individuals of the same species, having +slightly different constitutions or structure, would often succeed +better in the one country than in the other, and thus by a process of +"natural selection," as will hereafter be more fully explained, two +sub-breeds might be formed. This, perhaps, partly explains what has +been remarked by some authors, namely, that the varieties kept by +savages have more of the character of species than the varieties kept +in civilised countries. + +On the view here given of the all-important part which selection by +man has played, it becomes at once obvious, how it is that our +domestic races show adaptation in their structure or in their habits +to man's wants or fancies. We can, I think, further understand the +frequently abnormal character of our domestic races, and likewise +their differences being so great in external characters and relatively +so slight in internal parts or organs. Man can hardly select, or only +with much difficulty, any deviation of structure excepting such as is +externally visible; and indeed he rarely cares for what is internal. +He can never act by selection, excepting on variations which are first +given to him in some slight degree by nature. No man would ever try to +make a fantail, till he saw a pigeon with a tail developed in some +slight degree in an unusual manner, or a pouter till he saw a pigeon +with a crop of somewhat unusual size; and the more abnormal or unusual +any character was when it first appeared, the more likely it would be +to catch his attention. But to use such an expression as trying to +make a fantail, is, I have no doubt, in most cases, utterly incorrect. +The man who first selected a pigeon with a slightly larger tail, never +dreamed what the descendants of that pigeon would become through +long-continued, partly unconscious and partly methodical selection. +Perhaps the parent bird of all fantails had only fourteen +tail-feathers somewhat expanded, like the present Java fantail, or +like individuals of other and distinct breeds, in which as many as +seventeen tail-feathers have been counted. Perhaps the first +pouter-pigeon did not inflate its crop much more than the turbit now +does the upper part of its oesophagus,--a habit which is disregarded +by all fanciers, as it is not one of the points of the breed. + +Nor let it be thought that some great deviation of structure would be +necessary to catch the fancier's eye: he perceives extremely small +differences, and it is in human nature to value any novelty, however +slight, in one's own possession. Nor must the value which would +formerly be set on any slight differences in the individuals of the +same species, be judged of by the value which would now be set on +them, after several breeds have once fairly been established. Many +slight differences might, and indeed do now, arise amongst pigeons, +which are rejected as faults or deviations from the standard of +perfection of each breed. The common goose has not given rise to any +marked varieties; hence the Thoulouse and the common breed, which +differ only in colour, that most fleeting of characters, have lately +been exhibited as distinct at our poultry-shows. + +I think these views further explain what has sometimes been +noticed--namely that we know nothing about the origin or history of +any of our domestic breeds. But, in fact, a breed, like a dialect of a +language, can hardly be said to have had a definite origin. A man +preserves and breeds from an individual with some slight deviation of +structure, or takes more care than usual in matching his best animals +and thus improves them, and the improved individuals slowly spread in +the immediate neighbourhood. But as yet they will hardly have a +distinct name, and from being only slightly valued, their history will +be disregarded. When further improved by the same slow and gradual +process, they will spread more widely, and will get recognised as +something distinct and valuable, and will then probably first receive +a provincial name. In semi-civilised countries, with little free +communication, the spreading and knowledge of any new sub-breed will +be a slow process. As soon as the points of value of the new sub-breed +are once fully acknowledged, the principle, as I have called it, of +unconscious selection will always tend,--perhaps more at one period +than at another, as the breed rises or falls in fashion,--perhaps more +in one district than in another, according to the state of +civilisation of the inhabitants--slowly to add to the characteristic +features of the breed, whatever they may be. But the chance will be +infinitely small of any record having been preserved of such slow, +varying, and insensible changes. + +I must now say a few words on the circumstances, favourable, or the +reverse, to man's power of selection. A high degree of variability is +obviously favourable, as freely giving the materials for selection to +work on; not that mere individual differences are not amply +sufficient, with extreme care, to allow of the accumulation of a large +amount of modification in almost any desired direction. But as +variations manifestly useful or pleasing to man appear only +occasionally, the chance of their appearance will be much increased by +a large number of individuals being kept; and hence this comes to be +of the highest importance to success. On this principle Marshall has +remarked, with respect to the sheep of parts of Yorkshire, that "as +they generally belong to poor people, and are mostly IN SMALL LOTS, +they never can be improved." On the other hand, nurserymen, from +raising large stocks of the same plants, are generally far more +successful than amateurs in getting new and valuable varieties. The +keeping of a large number of individuals of a species in any country +requires that the species should be placed under favourable conditions +of life, so as to breed freely in that country. When the individuals +of any species are scanty, all the individuals, whatever their quality +may be, will generally be allowed to breed, and this will effectually +prevent selection. But probably the most important point of all, is, +that the animal or plant should be so highly useful to man, or so much +valued by him, that the closest attention should be paid to even the +slightest deviation in the qualities or structure of each individual. +Unless such attention be paid nothing can be effected. I have seen it +gravely remarked, that it was most fortunate that the strawberry began +to vary just when gardeners began to attend closely to this plant. No +doubt the strawberry had always varied since it was cultivated, but +the slight varieties had been neglected. As soon, however, as +gardeners picked out individual plants with slightly larger, earlier, +or better fruit, and raised seedlings from them, and again picked out +the best seedlings and bred from them, then, there appeared (aided by +some crossing with distinct species) those many admirable varieties of +the strawberry which have been raised during the last thirty or forty +years. + +In the case of animals with separate sexes, facility in preventing +crosses is an important element of success in the formation of new +races,--at least, in a country which is already stocked with other +races. In this respect enclosure of the land plays a part. Wandering +savages or the inhabitants of open plains rarely possess more than one +breed of the same species. Pigeons can be mated for life, and this is +a great convenience to the fancier, for thus many races may be kept +true, though mingled in the same aviary; and this circumstance must +have largely favoured the improvement and formation of new breeds. +Pigeons, I may add, can be propagated in great numbers and at a very +quick rate, and inferior birds may be freely rejected, as when killed +they serve for food. On the other hand, cats, from their nocturnal +rambling habits, cannot be matched, and, although so much valued by +women and children, we hardly ever see a distinct breed kept up; such +breeds as we do sometimes see are almost always imported from some +other country, often from islands. Although I do not doubt that some +domestic animals vary less than others, yet the rarity or absence of +distinct breeds of the cat, the donkey, peacock, goose, etc., may be +attributed in main part to selection not having been brought into +play: in cats, from the difficulty in pairing them; in donkeys, from +only a few being kept by poor people, and little attention paid to +their breeding; in peacocks, from not being very easily reared and a +large stock not kept; in geese, from being valuable only for two +purposes, food and feathers, and more especially from no pleasure +having been felt in the display of distinct breeds. + +To sum up on the origin of our Domestic Races of animals and plants. I +believe that the conditions of life, from their action on the +reproductive system, are so far of the highest importance as causing +variability. I do not believe that variability is an inherent and +necessary contingency, under all circumstances, with all organic +beings, as some authors have thought. The effects of variability are +modified by various degrees of inheritance and of reversion. +Variability is governed by many unknown laws, more especially by that +of correlation of growth. Something may be attributed to the direct +action of the conditions of life. Something must be attributed to use +and disuse. The final result is thus rendered infinitely complex. In +some cases, I do not doubt that the intercrossing of species, +aboriginally distinct, has played an important part in the origin of +our domestic productions. When in any country several domestic breeds +have once been established, their occasional intercrossing, with the +aid of selection, has, no doubt, largely aided in the formation of new +sub-breeds; but the importance of the crossing of varieties has, I +believe, been greatly exaggerated, both in regard to animals and to +those plants which are propagated by seed. In plants which are +temporarily propagated by cuttings, buds, etc., the importance of the +crossing both of distinct species and of varieties is immense; for the +cultivator here quite disregards the extreme variability both of +hybrids and mongrels, and the frequent sterility of hybrids; but the +cases of plants not propagated by seed are of little importance to us, +for their endurance is only temporary. Over all these causes of Change +I am convinced that the accumulative action of Selection, whether +applied methodically and more quickly, or unconsciously and more +slowly, but more efficiently, is by far the predominant Power. + + Modified: logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/control/PackageTest.java ============================================================================== --- logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/control/PackageTest.java (original) +++ logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/control/PackageTest.java Wed Mar 4 21:05:53 2009 @@ -15,6 +15,6 @@ @RunWith(Suite.class) -@SuiteClasses({RandomUtilTest.class}) +@SuiteClasses({}) public class PackageTest { } \ No newline at end of file Modified: logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/control/ScenarioRandomUtil.java ============================================================================== --- logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/control/ScenarioRandomUtil.java (original) +++ logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/control/ScenarioRandomUtil.java Wed Mar 4 21:05:53 2009 @@ -1,17 +1,18 @@ -/** - * LOGBack: the reliable, fast and flexible logging library for Java. - * - * Copyright (C) 1999-2005, QOS.ch, LOGBack.com - * - * This library is free software, you can redistribute it and/or - * modify it under the terms of the GNU Lesser General Public License as - * published by the Free Software Foundation. +/** + * Logback: the generic, reliable, fast and flexible logging framework. + * + * Copyright (C) 2000-2009, QOS.ch + * + * This library is free software, you can redistribute it and/or modify it under + * the terms of the GNU Lesser General Public License as published by the Free + * Software Foundation. */ package ch.qos.logback.classic.control; import java.util.Random; import ch.qos.logback.classic.Level; +import ch.qos.logback.classic.corpus.RandomUtil; public class ScenarioRandomUtil { private final static long SEED = 74130; @@ -49,7 +50,7 @@ } public static String randomLoggerName(int average, int stdDeviation) { - int depth = gaussianAsPositiveInt(average, stdDeviation); + int depth = RandomUtil.gaussianAsPositiveInt(random, average, stdDeviation); StringBuffer buf = new StringBuffer(); for (int i = 0; i < depth; i++) { if (i != 0) { @@ -62,7 +63,7 @@ public static String randomId() { - int len = gaussianAsPositiveInt(AVERAGE_ID_LEN, AVERAGE_ID_DEV); + int len = RandomUtil.gaussianAsPositiveInt(random, AVERAGE_ID_LEN, AVERAGE_ID_DEV); StringBuffer buf = new StringBuffer(); for (int i = 0; i < len; i++) { int offset = random.nextInt(26); @@ -72,31 +73,6 @@ return buf.toString(); } - /** - * Approximate a gaussian distrib with only only positive integer values - * - * @param average - * @param stdDeviation - * @return - */ - public static int gaussianAsPositiveInt(int average, int stdDeviation) { - if (average < 1) { - throw new IllegalArgumentException( - "The average must not be smaller than 1."); - } - - if (stdDeviation < 1) { - throw new IllegalArgumentException( - "The stdDeviation must not be smaller than 1."); - } - - double d = random.nextGaussian() * stdDeviation + average; - int result = 1; - if (d > 1.0) { - result = (int) Math.round(d); - } - return result; - } /** * Returns 3 for root, 3 for children of root, 9 for offspring of generation 2 @@ -114,7 +90,7 @@ return 9; } else { if (shouldHaveChildrenWithProbabilitz(0.5)) { - return gaussianAsPositiveInt(AVERAGE_CHILDREN_COUNT, CHILDREN_COUNT_VAR); + return RandomUtil.gaussianAsPositiveInt(random, AVERAGE_CHILDREN_COUNT, CHILDREN_COUNT_VAR); } else { return 0; } Added: logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/corpus/CorpusMakerUtil.java ============================================================================== --- (empty file) +++ logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/corpus/CorpusMakerUtil.java Wed Mar 4 21:05:53 2009 @@ -0,0 +1,156 @@ +/** + * Logback: the generic, reliable, fast and flexible logging framework. + * + * Copyright (C) 2000-2009, QOS.ch + * + * This library is free software, you can redistribute it and/or modify it under + * the terms of the GNU Lesser General Public License as published by the Free + * Software Foundation. + */ +package ch.qos.logback.classic.corpus; + +import java.util.List; +import java.util.Random; + +import ch.qos.logback.classic.Level; + +public class CorpusMakerUtil { + + // level distribution is determined by the following table + // it corresponds to TRACE 20%, DEBUG 30%, INFO 30%, WARN 10%, + // ERROR 10%. See also getRandomLevel() method. + static final double[] LEVEL_DISTRIBUTION = new double[] { .2, .5, .8, .9 }; + + // messages will have no arguments 90% of the time, one argument in 3%, two + // arguments in 3% and three arguments in 3% of cases + static final double[] ARGUMENT_DISTRIBUTION = new double[] { .90, .933, 0.966 }; + + static final double THROWABLE_PROPABILITY_FOR_WARNING = .1; + static final double THROWABLE_PROPABILITY_FOR_ERRORS = .3; + static final double NESTING_PROBABILITY = .5; + + static final int AVERAGE_LOGGER_NAME_PARTS = 6; + static final int STD_DEV_FOR_LOGGER_NAME_PARTS = 3; + + static final int AVERAGE_MESSAGE_WORDS = 8; + static final int STD_DEV_FOR_MESSAGE_WORDS = 4; + + final Random random; + List<String> worldList; + + CorpusMakerUtil(long seed, List<String> worldList) { + random = new Random(seed); + this.worldList = worldList; + + } + + String getRandomWord() { + int size = worldList.size(); + int randomIndex = random.nextInt(size); + return worldList.get(randomIndex); + } + + int[] getRandomAnchorPositions(int wordCount, int numAnchors) { + // note that the same position may appear multiple times in + // positionsIndex, but without serious consequences + int[] positionsIndex = new int[numAnchors]; + for (int i = 0; i < numAnchors; i++) { + positionsIndex[i] = random.nextInt(wordCount); + } + return positionsIndex; + } + + private String[] getRandomWords(int n) { + String[] wordArray = new String[n]; + for (int i = 0; i < n; i++) { + wordArray[i] = getRandomWord(); + } + return wordArray; + } + + MessageEntry getRandomMessageEntry() { + int numOfArguments = getNumberOfMessageArguments(); + Object[] argumentArray = null; + if (numOfArguments > 0) { + argumentArray = new Object[numOfArguments]; + for (int i = 0; i < numOfArguments; i++) { + argumentArray[i] = new Long(random.nextLong()); + } + } + int wordCount = RandomUtil.gaussianAsPositiveInt(random, + AVERAGE_MESSAGE_WORDS, STD_DEV_FOR_MESSAGE_WORDS); + String[] wordArray = getRandomWords(wordCount); + + int[] anchorPositions = getRandomAnchorPositions(wordCount, numOfArguments); + for (int anchorIndex : anchorPositions) { + wordArray[anchorIndex] = "{}"; + } + + StringBuilder sb = new StringBuilder(); + for (int i = 1; i < wordCount; i++) { + sb.append(getRandomWord()).append(' '); + } + sb.append(getRandomWord()); + + return new MessageEntry(sb.toString(), argumentArray); + } + + Throwable buildThrowable(double i) { + return null; + } + + Throwable getRandomThrowable(Level level) { + double rn = random.nextDouble(); + if ((level == Level.WARN && rn < THROWABLE_PROPABILITY_FOR_WARNING) + || (level == Level.ERROR && rn < THROWABLE_PROPABILITY_FOR_ERRORS)) { + return ExceptionBuilder.build(random, NESTING_PROBABILITY); + } else { + return null; + } + } + + int getNumberOfMessageArguments() { + double rn = random.nextDouble(); + if (rn < ARGUMENT_DISTRIBUTION[0]) { + return 0; + } + if (rn < ARGUMENT_DISTRIBUTION[1]) { + return 1; + } + if (rn < ARGUMENT_DISTRIBUTION[2]) { + return 2; + } + return 3; + } + + String getRandomLoggerName() { + int parts = RandomUtil.gaussianAsPositiveInt(random, + AVERAGE_LOGGER_NAME_PARTS, STD_DEV_FOR_LOGGER_NAME_PARTS); + StringBuilder sb = new StringBuilder(); + for (int i = 1; i < parts; i++) { + sb.append(getRandomWord()).append('.'); + } + sb.append(getRandomWord()); + return sb.toString(); + } + + Level getRandomLevel() { + double rn = random.nextDouble(); + if (rn < LEVEL_DISTRIBUTION[0]) { + return Level.TRACE; + } + if (rn < LEVEL_DISTRIBUTION[1]) { + return Level.DEBUG; + } + + if (rn < LEVEL_DISTRIBUTION[2]) { + return Level.INFO; + } + + if (rn < LEVEL_DISTRIBUTION[3]) { + return Level.WARN; + } + + return Level.ERROR; + } +} Added: logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/corpus/ExceptionBuilder.java ============================================================================== --- (empty file) +++ logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/corpus/ExceptionBuilder.java Wed Mar 4 21:05:53 2009 @@ -0,0 +1,33 @@ +package ch.qos.logback.classic.corpus; + +import java.io.IOException; +import java.util.Random; + +public class ExceptionBuilder { + + static Throwable build(Random r, double nestingProbability) { + double rn = r.nextDouble(); + boolean nested = false; + if (rn < nestingProbability) { + nested = true; + } + + Throwable cause = null; + if(nested) { + cause = makeThrowable(r, null); + } + return makeThrowable(r, cause); + } + + private static Throwable makeThrowable(Random r, Throwable cause) { + int exType = r.nextInt(4); + switch(exType) { + case 0: return new IllegalArgumentException("an illegal argument was passed", cause); + case 1: return new Exception("this is a test", cause); + case 2: return new IOException("an io error occured", cause); + case 3: return new OutOfMemoryError("ran out of memory"); + } + return null; + } + +} Added: logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/corpus/MessageEntry.java ============================================================================== --- (empty file) +++ logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/corpus/MessageEntry.java Wed Mar 4 21:05:53 2009 @@ -0,0 +1,27 @@ +package ch.qos.logback.classic.corpus; + +public class MessageEntry { + + + final String message; + final Object[] argumentArray; + + public MessageEntry(String message) { + this(message, null); + } + + + public MessageEntry(String message, Object[] argumentArray) { + this.message = message; + this.argumentArray = argumentArray; + } + + public String getMessage() { + return message; + } + + public Object[] getArgumentArray() { + return argumentArray; + } + +} Added: logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/corpus/RandomUtil.java ============================================================================== --- (empty file) +++ logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/corpus/RandomUtil.java Wed Mar 4 21:05:53 2009 @@ -0,0 +1,42 @@ +/** + * Logback: the generic, reliable, fast and flexible logging framework. + * + * Copyright (C) 2000-2009, QOS.ch + * + * This library is free software, you can redistribute it and/or modify it under + * the terms of the GNU Lesser General Public License as published by the Free + * Software Foundation. + */ +package ch.qos.logback.classic.corpus; + +import java.util.Random; + +public class RandomUtil { + + + /** + * Approximate a gaussian distrib with only positive integer values + * + * @param average + * @param stdDeviation + * @return + */ + static public int gaussianAsPositiveInt(Random random, int average, int stdDeviation) { + if (average < 1) { + throw new IllegalArgumentException( + "The average must not be smaller than 1."); + } + + if (stdDeviation < 1) { + throw new IllegalArgumentException( + "The stdDeviation must not be smaller than 1."); + } + + double d = random.nextGaussian() * stdDeviation + average; + int result = 1; + if (d > 1.0) { + result = (int) Math.round(d); + } + return result; + } +} Added: logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/corpus/TextFileUtil.java ============================================================================== --- (empty file) +++ logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/corpus/TextFileUtil.java Wed Mar 4 21:05:53 2009 @@ -0,0 +1,34 @@ +package ch.qos.logback.classic.corpus; + +import java.io.BufferedReader; +import java.io.IOException; +import java.util.ArrayList; +import java.util.List; + +public class TextFileUtil { + + //FileReader fr = new FileReader(filename); + //BufferedReader br = new BufferedReader(fr); + + public static List<String> toWords(BufferedReader br) throws IOException { + + + // (\\d+)$ + //String regExp = "^(\\d+) "+ msg + " ([\\dabcdef-]+)$"; + //Pattern p = Pattern.compile(regExp); + String line; + + List<String> wordList = new ArrayList<String>(); + + while ((line = br.readLine()) != null) { + //line = line.replaceAll("\\p{Punct}+", " "); + String[] words = line.split("\\s"); + for(String word: words) { + wordList.add(word); + } + } + br.close(); + + return wordList; + } +} Added: logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/corpusTest/FileToWord.java ============================================================================== --- (empty file) +++ logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/corpusTest/FileToWord.java Wed Mar 4 21:05:53 2009 @@ -0,0 +1,32 @@ +package ch.qos.logback.classic.corpusTest; + +import static org.junit.Assert.*; + +import java.io.BufferedReader; +import java.io.IOException; +import java.io.StringReader; +import java.util.List; + +import org.junit.Test; + +import ch.qos.logback.classic.corpus.TextFileUtil; + +public class FileToWord { + + @Test + public void smoke() throws IOException { + String s = "When on board H.M.S. 'Beagle,' as naturalist, I was much struck with\r\n" + + "certain facts in the distribution of the inhabitants of South America,\r\n" + + "and in the geological relations of the present to the past inhabitants\r\n" + + "of that continent."; + + StringReader sr = new StringReader(s); + BufferedReader br = new BufferedReader(sr); + List<String> wordList = TextFileUtil.toWords(br); + assertEquals(38, wordList.size()); + assertEquals("When", wordList.get(0)); + assertEquals("'Beagle,'", wordList.get(4)); + assertEquals("of", wordList.get(17)); + + } +} Added: logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/corpusTest/RandomUtilTest.java ============================================================================== --- (empty file) +++ logback/trunk/logback-classic/src/test/java/ch/qos/logback/classic/corpusTest/RandomUtilTest.java Wed Mar 4 21:05:53 2009 @@ -0,0 +1,43 @@ +package ch.qos.logback.classic.corpusTest; + +import static org.junit.Assert.assertEquals; + +import java.util.Random; + +import org.junit.Test; + +import ch.qos.logback.classic.corpus.RandomUtil; + + +public class RandomUtilTest { + + + @Test + public void smoke() { + + int EXPECTED_AVERAGE = 6; + int EXPECTED_STD_DEVIATION = 3; + + long now = System.currentTimeMillis(); + Random r = new Random(now); + int len = 3000; + int[] valArray = new int[len]; + for(int i = 0; i < len; i++) { + valArray[i] = RandomUtil.gaussianAsPositiveInt(r, EXPECTED_AVERAGE, EXPECTED_STD_DEVIATION); + } + double avg = average(valArray); + for(int x: valArray) { + System.out.println(""+x); + } + assertEquals(EXPECTED_AVERAGE, avg, 0.1); + } + + public double average(int[] va) { + double avg = 0; + for(int i = 0; i < va.length; i++) { + avg = (avg*i+va[i])/(i+1); + } + return avg; + } + +}