Innumerable otherexamples could be given

I have discussed the probable origin of domestic pigeons at someet quite insufficient, length, because when I first kept pigeons andwatched the several kinds, knowing well how true they bred, I felt fullyas much difficulty in believing that they could ever have descendedfrom a common parent, as any naturalist could in coming to a similarconclusion in regard to the many species of finches, or other largegroups of birds, in nature. One circumstance has struck me muchnamely, that all the breeders of the various domestic animals and thecultivators of plants, with whom I have ever conversed, or whosetreatises I have read, are firmly convinced that the several breeds towhich each has attended, are descended from so many aboriginallydistinct species.

Ask, as I have asked, a celebrated raiser of Herefordcattle, whether his cattle might not have descended from longhorns,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 mainbreed was descended from a distinct species. Van Mons, in his treatiseon pears and apples, shows how utterly he disbelieves that the severalsorts, for instance a Ribston-pippin or Codlin-apple, could ever haveproceeded from the seeds of the same tree. Innumerable otherexamples could be given. The explanation, I think, is simple: fromlong-continued study they are strongly impressed with the differencesbetween the several races; and though they well know that each racevaries slightly, for they win their prizes by selecting such slightdifferences, yet they ignore all general arguments, and refuse to sumup in their minds slight differences accumulated during manysuccessive generations May not those naturalists who, knowing farless of the laws of inheritance than does the breeder, and knowing nomore than he does of the intermediate links in the long lines of descentyet admit that many of our domestic races have descended from thesame parents- may they not learn a lesson of caution, when theyderide the idea of species in a state of nature being lineal descendantsof other species?

Selection. Let us now briefly consider the steps by which domesticraces have been produced, either from one or from several alliedspecies. Some little effect may, perhaps, be attributed to the directaction of the external conditions of life. and some little to habit: but hewould be a bold man who would account by such agencies for thedifferences of a dray and race horse, a greyhound and bloodhound, acarrier and tumbler pigeon. One of the most remarkable features in ourdomesticated races is that we see in them adaptation, not indeed tothe animal's or plant's own good, but to man's use or fancy. Somevariations useful to him have probably arisen suddenly, or by one stepmany botanists, for instance, believe that the fuller's teazle, with itshooks, which cannot be rivalled by any mechanical contrivance, is onlya variety of the wild Dipsacus; and this amount of change may havesuddenly arisen in a seedling. So it has probably been with the turnspitdog, and this is known to have been the case with the ancon sheepBut when we compare the dray-horse and race-horse, the dromedaryand camel, the various breeds of sheep fitted either for cultivated landor mountain pasture, with the wool of one breed good for one purposeand that of another breed for another purpose: when we compare themany breeds of dogs, each good for man in very different ways: whenwe compare the game-cock, so pertinacious in battle, with other breedsso little quarrelsome, with everlasting layers which never desire to sitand with the bantam so small and elegant, when we compare the hostof agricultural, culinary, orchard, and flower-garden races of plantsmost useful to man at different seasons and for different purposes, orso beautiful in his eyes, we must, I think, look further than to merevariability. We cannot suppose that all the breeds were suddenlyproduced as perfect and as useful as we now see them; indeed, inseveral cases, we know that this has not been their history. The key isman's power of accumulative selection: nature gives successivevariations: man adds them up in certain directions useful to him. In thissense he may be said to make for himself useful breeds

The great power of this principle of selection is not hypothetical. It iscertain that several of our eminent breeders have, even within a singleifetime, modified to a large extent some breeds of cattle and sheep. Inorder fully to realize what they have done, it is almost necessary to readseveral of the many treatises devoted to this subject, and to inspect theanimals. Breeders habitually speak of an animal's organisation assomething quite plastic, which they can model almost as they pleasehad space I could quote numerous passages to this effect fromhighly competent authorities. Youatt, who was probably betteracquainted with the works of agriculturalists than almost any otherindividual, and who was himself a very good judge of an animal, speaksof the principle of selection as that which enables the agriculturist, notonly to modify the character of his flock, but to change it altogether. Itis the magicians wand, by means of which he may summon into lifewhatever form and mould he pleases. Lord Somerville, speaking ofwhat breeders have done for sheep, says: -It would seem as if theyhad chalked out upon a wall a form perfect in itself, and then had givenit existence. That most skilful breeder, Sir John Sebright, used to say.with respect to pigeons, that he would produce any given feather inthree years, but it would take him six years to obtain head and beakIn Saxony the importance of the principle of selection in regard tomerino sheep is so fully recognised, that men follow it as a trade: thesheep are placed on a table and are studied, like a picture by aconnoisseur: this is done three times at intervals of months. and thesheep are each time marked and classed, so that the very best mayultimately be selected for breedingWhat English breeders have actually effected is proved by theenormous prices given for animas with a good pedigree, and thesehave now been exported to almost every quarter of the world. Theimprovement is by no means generally due to crossing different breeds,all the best breeders are strongly opposed to this practice, excepsometimes amongst closely allied sub-breeds. And when a cross hasbeen made, the closest selection is far more indispensable even thanin ordinary cases. If selection consisted merely in separating some verydistinct variety, and breeding from it, the principle would be so obviousas hardly to be worth notice; but its importance consists in the greateffect produced by the accumulation in one direction, during successivegenerations, of dfferences absolutely inappreciable by an uneducatedeye-differences which I for one have vainly attempted to appreciateNot one man in a thousand has accuracy of eye and judgementsufficient to become an eminent breeder. If gifted with these qualitiesand he studies his subject for years, and devotes his lifetime to it withndomitable perseverance, he will succeed, and may make greatmprovements; if he wants any of these qualities, he will assuredly failFew would readily believe in the natural capacity and years of practicerequisite to become even a skilful pigeon fancier