From Edward Blyth [30 September or 7 October 1855]1
Notes for Mr Darwin.
The 2d Vol. of Lyell’s ‘Principles’2 not being conveniently at hand, & requiring a hot drive to go & fetch it, I avail myself of a quiet Sunday morning to attempt a sort of summary or recapitulation of much that I have before treated on; giving the results of subsequent meditation, & placing in juxta-position, perhaps, facts & considerations which may conduce to farther generalizations & additional suggestions.
Firstly, then, it seems to be a favorite notion that the more marked varieties of animals (& of plants) have not been very gradually produced, but that a short time sufficed to attain the limits of variation, & those distinctions which have ever since been perpetuated.
There are no recorded facts, however, relative to the origination of a marked variety, to bear out this theory or rather hypothesis; and sufficient time has surely elapsed since the introduction of Old World animals into the New, & vice versâ, to have furnished, in all probability, at least one or two illustrations. Instead of which, we have instances of acquired habits becoming heriditary instincts, as with the Peccary-hunting Dogs in S. America, & in Australia the Kangaroo Dogs. Prichard’s notion of the “Creole fowls” I think that I have sufficiently demolished.3 By the way, what do we know of the races of the fowls so numerous among the Niger tribes of Africa? All probably introduced originally through Egypt! But has no peculiar race originated in all Africa? As for the “Otter Sheep”, they merely illustrate a malformation or deformity, which has become congenital; & this through direct human interference, by careful selection of parents! Such a race may, in like manner, have originated anywhere, & cannot therefore be ascribed to any peculiarity of the American climate. It is analogous to the Turnspit Dog (which has often been casually produced); & we have the still more curious instance, among birds, of the “Penguin Ducks” common in the Philippines. Such cases, however, are suggestive of the origin of abnormal varieties generally; which I incline to ascribe to direct interference on the part of man, & his immediate & intentional superintendence of the propagation of animals descended from a casual monstrosity! E.g. Turn-crested Canaries and Lob-eared Rabbits probably within the past century; & floral varieties without number.
We should distinguish the varieties of animals into normal and abnormal; the former exemplified by the European races of cattle, sheep, &c, which retain the normal conformation of other and wild animals, or present aberrations of merely trivial import, such as might even characterize a wild species. The races of mankind fall under this division; while the “Porcupine family” & 6-digital folks represent the other,4 & certain Hottentot peculiarities tend in the same direction. Suppose we were to select from the Bojesman race,5 & continue the propagation from the choicest specimens only, for a few generations! Could the result be doubted? Any more than with mere albinos, &c &c? Have you seen Knox’s curious volume on the races of mankind?6
I think that the designation breed should be restricted to those artificial races which have been intentionally produced by the admixture of normal varieties, for the special attainment of calculated results; & which artificial races require much skilful management to preserve in their integrity, by an occasional infusion of fresh blood from the normal races from which they had descended. Mr So & so’s particular breed of Sheep, for instance, &c &c.
By abnormal varieties, as distinguished from normal, I mean such as we have no reason to believe had any prototypes in wild nature: as fat-rumped & fat-tailed Sheep, polycerate do. & Goats, hornless do.7 Bovine cattle (individuals only of which do sometimes, though very rarely, occur wild,—as the Empress Josephine’s hornless Springbok—Gazella euchore, & the American animal designated Ixalus probaton by Ogilby);8 —long and pendent-eared Goats, the Silky-coated Angora do, & cat & Rabbit, solidungular or “Donkey-footed” Swine, & Spaniels, Poodles, &c. among dogs (& the marked races of dogs seem to be diminishing rather than increasing in number, witness the bloodhound, Maltese dog, &c).— Among birds, the fancy Pigeons, & the very numerous abnormal races of poultry,—as silky, frizzled, rumpless, 5-toed, feather-legged, crested; double & multiple-combed & even coarse legged (so different from their wild congeners). Geese & Ducks with downy top-knots may be added; & the singular varieties of Cyprinus auratus & C. macropthalmus. Also the Cutch race of horses.
It is remarkable that there is no Double-spurred race of domestic fowls; & the more so as several wild Gallinaceous genera are typically double-spurred, & this character is in them subject to variation, one tarsus of the same bird often bearing 3 spurs & the other 1 only, & the spurs also being variously situate: e.g. Polyptectron, Galloperdix, Ithaginis, & various African Partridges. How does this plurality of spurs tally with the theory that the tarsal spur represents the thumb or first digit? One or two wing-spurs being also severally met with in various birds.
I have probably before remarked on the essential difference between the clothing of the legs & toes in the feather-legged fowls & Pigeons, from that of various Falconidæ, Strigidæ, Grouse, &c (to which it has been compared). The legs of those races of fowls & Pigeons bearing feathers analogous to those of the wings; & accordingly similar over the corresponding bones of the wing & of the leg & foot: no instance of this occurring in a wild bird; wherefore it is an abnormal variation, which it would not have been (in the particular sense here implied) had the covering of the leg resembled that of a Grouse—or Ptarmigan.
Buffon I think it was who first remarked that no wild quadruped has pendent ears! He might have excepted the Elephant; but I can remember no other instance.9 They are pendent in various domestic races of dogs, swine, rabbits, humped cattle, sheep, & goats. Moreover no wild Canis has the more or less erect & curled tail of most domestic dogs; & all the wild swine have a straight tail, as in the Elephant & Rhinoceros. The curious stiffly twisted tail figured and described by F. Cuvier of Paradoxurus (whence the name) typus, is abnormal to the species and of rare occurence.10 Wild Canis has always a brush-tail.
It is a remarkable fact that whilst almost every race of domestic Sheep has long tails, the numerous distinct species of wild Sheep have exceedingly short tails; with the little known exception of O. californiana, Douglass, which is described to have a tail 18in. long, & the very aberrant O. tragelaphus which has also a longish tail, and there is certainly no reason to suppose that either of the latter has ever been domesticated.11 Hodgson thinks that the elongation of the tail in domestic Sheep is a result of domestication; but this I doubt much.12 In what other animal has the number of caudal vertebræ increased at all (while in Sheep so amazingly); not even in the affined Goat genus, the domestic varieties of which are also so numerous. True, the fantail Pigeon has an increased number of caudal feathers; but this is another affair. Whatever the wild Sheep of St Kilda formerly were, these are understood to have been long-tailed. Can they have been the last remnant of a wild species elsewhere extirpated, & from which the European domestic types have descended? Moreover, is the fleece of the domestic Sheep really an abnormal product, although observed in no existing species of wild Ovis at present known? (Schinz figures something very like it in the Siberian Ibex!)13 And is the assumption of a smooth hairy coat by Sheep in certain torrid regions a proof of a reversion to the primal type, when we know that the wild Sheep are chiefly found in elevated regions near the snow line, & have spongy coats like that of the Rein Deer, Musk, & other inhabitants of the coldest climates. O. tragelaphus of the Atlas is, I think, an exception, with a Goat-like covering; & this inhabits a comparatively warm climate. My impression is, that the wild type or types of (at least) our European domestic Sheep are lost; & it is even remarkable that none coexists with the Chamois & Ibices in the great mountain chains of Europe, & only the Moufflons of Corsica & Cyprus, & proceeding eastward the next we meet with is O. Gmelini on the Taurus, followed soon by O. Vignei on the Elburz. I now return to generalities.
The varieties of domestic animals may be conveniently distributed into 1, Those of which we know the origin,—2, Those of which the origin (from existing wild types) is probable,—and 3, Those of which the origin is unknown.
With the exception of the Knobbed Goose, and the domestic collared Turtle-dove, I think all domestic birds will come under the first category (though is the aboriginally wild Cygnus olor, or Mute Swan, particularly well known?,) To me the evidence is satisfactory as regards the Fowl, Turkey, Peafowl, Guinea-fowl, Europn Goose, Duck, Musk do, Pigeon & Canary (although I have never seen the wild Canary). Of these the third & fourth only deviate from the wild species sometimes in colouring; & the white of each have been selected and bred from, so that the albinism has become permanent. The semi-wild Pheasant & Fallow Deer vary to a greater extent. The Fowl and the Pigeon are, beyond all comparison, the most varied of domestic birds; and both present numerous abnormal varieties, which (as we may feel quite sure) never had prototypes in wild nature. If we are satisfied, therefore (as I am), of this, & furthermore that all the domestic varieties of fowls & pigeons are as identical in species as those of dogs, or of humped, or of humpless cattle, or of goats, or horses (which may or may not have resulted from an admixture of aboriginally wild races; but we will pass over this question now, & consider each of the above to constitute a single species),— If, then, we discard from the enquiry all the manifestly abnormal varieties, and at the same time regard these as specifically identical with the others,—in still other words, taking the whole as specifically identical, we confine our attention to those which exhibit no abnormal variation equally from all other wild birds as from their own wild progenitors, then the enquiry becomes not a little narrowed & proportionally facilitated, & we no longer find difficulty in recognising the wild origins of both domestic fowls and pigeons. I have argued the fowl question before, & it succinctly resolves into this,—1, There appear to be but 3 wild species of typical Gallus, with single indented comb, 2 lateral throat-wattles, and the hackled feathers upon the neck. (The Gallus furcatus of Java is thus excluded, as not a typical species; and the G. œneus, Tem., is now known to be a hybrid raised in confinement between G. furcatus & a common hen).— 2, Of the 3 wild typical Galli, one (G. Stanleyi, v. Lafayettei) is quite peculiar to Ceylon, and is abundantly distinct, specifically, from all domestic fowls.— 3, The same remark applies, even more emphatically, to G. Sonneratii, which is peculiar to the peninsula of India S. of the Vindhyian range. Moreover, both of these species have a totally different voice, in every note uttered, from all races of the common fowl.— 4. The third species, G. ferrugineus (v. bankivus,—it should have been G. alector), which is diffused in suitable localities over all N. India to the base of the Himalaya, also throughout the countries bordering the Bay of Bengal to the eastward, & probably all the Indo-Chinese countries, absolutely & essentially conforms to the type of the domestic fowl in all its multitudinous varieties, fully as much so as the Mallard does to the domestic drake; or the wild to the tame Turkey! The voice is the same, & it corresponds feather by feather with many domestic individuals; while the deeply incised comb is peculiar to it and to the domestic races (with scarely an exception among the latter). But you will have seen my observations on Jungle-fowl, in the communications to the Ann. Mag. N. H. 14
Pass we therefore to the abnormal varieties of domestic fowls; respecting which one important generalization occurs to me, which is that all appear to have originated in those countries to which the species is indigenous, or in the immediate neighbourhood of those countries. The crested Polish may be an exception; & this is one of the least abnormal among them. Though now diffused over the whole habitable globe, & so thoroughly reclaimed that it does not appear to have anywhere returned to wildness, though subjected to the extremes of climatal and local influence, it does not appear that the latter have produced appreciable result; & from this and analogous facts which I could cite, I do think that those supposed influences have been immensely over-rated! China, Indo-China, & the Malay countries, though more especially the two former, seem to me to be the regions in which the abnormal varieties of domestic fowls have originated,—not India, because I know of none peculiar to it, & the Hindus have some absurd prejudice against common poultry (which I never could get explained), even the touch of them being contamination to these most inconsistent people. E.g. With all their absurd nonsense about food, they scruple not to drink filthy water, &c &c. Now the Chinese & Indo-Chinese are just the very people to be taken with any outlandish monstrosity, & to try & propagate it as a curiosity, & to keep such a breed up by selection of parents, the China-men evincing a most especial taste for monsters of all kinds (witness their carvings), & shewing the same perverted taste in their floriculture, dwarfs of trees, &c &c. The American “Otter Sheep” here comes in as an apt illustration, & no doubt many such varieties have been “improved” or intensified by judicious breeding; such as enables Pigeon-fanciers in India or in England to breed to a spot or feather. Another consideration is, that many (if not most) of these varieties have been transmitted probably from a very remote period, far anterior to the civilization of the British Isles; so that we have now, the sum (pretty nearly) of the variation exhibited during that long period, as fostered & carefully “bred” by a succession of “fanciers” during so many centuries. In other parts of the world, cæteris paribus, where the same tastes do not prevail as in the densely populated and (after their fashion) civilized nations of E. Asia, such varieties of the kind as may have arisen would scarcely have been preserved; an inference well worthy of remembrance! Bear in mind also the results obtained of late years in Europe & England especially, as the breeding of black, & of gold-spangled, & silver-spangled, Polish fowls, Bantams, &c— NB. The Bantams are much cherished in Burma, & seem to be native to the same region as the largest (& ugliest) of all fowls, the Cochin-chinese! In like manner, the smallest known breed of tame Sheep (the Purik of Moorcroft)15 is a compatriot of the largest known of domestic varieties!
Among the endless varieties of the fowl, we have, in China, some large & heavy-built feather-legged birds, akin to the Dorking (which Dixon has pretty well shewn to be of Chinese origin),16 the eggs of which are of a light buff hue, and are occasionally more or less speckled like those of Grouse! The egg of the Ceylon Jungle-fowl is, sometimes at least, freckled like that of a Guinea-fowl. Indeed, the variation in the eggs of some birds is worthy of notice, as especially in the well known instance of the Guillemot, Uria troille.
A most curious & quite unparalleled case of variableness of colouring in a wild animal occurs in the well known instance of the Ruff (Philomachus pugnax), at least the males during the breeding season, among which it is a phenomenon to find two alike; & at other seasons they are not all quite similar, for the pale-ruffed may still be distinguished from the dark-ruffed (even when they have not the ruff), & many of the former have a pure white neck; & they differ also in the colouring of the legs at all seasons.
Have the (alleged) varieties of Ursus arctos been sufficiently studied? As the Cinnamon Bear, Collared &c. Some are probably distinct.
Most extraordinary differences of size occur among some birds, even in the same flock,—as especially Numenius arquata, Limosa ægocephala, & Pelicans; also in a small Hawk of this country, the Accipiter virgatus, the female of which is much larger than the male, but both vary much in size. I consider the Limosa melanuroides of Gould (B. Australia)17 to be merely a small-sized L. ægocephala, such as I could procure here any day during the cold season.
It occurs to me to ask if any variation has yet been shewn by the Magellanic, Sandwich Id, & Falkland Id. Geese, which have now been reared for many generations in England?
Streaked & spotted animals often differ considerably in the markings of the two sides of their body; vide the Koodoo, or the Harnessed Antelope, or either of the Zebras, or Felinæ. The variation of the beautiful little Felis bengalensis is very considerable; and I have seen Jaguar skins absolutely like those of Leopards: but these were selected from a great many (by Sir R. Schomberg).18 Were the latter fact unknown, they might have been supposed distinct. Leopards also vary exceedingly.
So also with Tiger-moths (Arctia), & various shells, as Neritinæ, Ratittæ, & the beautiful Phasianellæ of V. D Land, Helix nemoralis is a familiar British instance; & the Bulimus perversus, which moreover is as often reversed as otherwise.
The same want of regularity in the markings, while the general character of them is retained, is observable in the leaves & petals, &c, of plants—E. g. Acuba japonica, & variegated hollies, & the petals of bizarre-carnations, tulips, balsams, &c., among cultivated flowers; camellias also, &c.
The species or varieties of the Rein Deer want looking to; especially the Tarandus platyrhynchus of Prof. Vrolik,19 and the Barrenground & Woodland Caribou of Sir J. Richardson. Of the latter, I take the first to be of the same race as the domesticated R.D. of Lapland, & the second to be the large race tamed in Siberia. See Richardson’s remarks on the physical similarity of the Amn Barrengrounds to Lapland;20 & no doubt the former region might also be rendered habitable by means of domesticated Rein Deer! I quote the following passage from an article on the Rein Deer which I wrote some years ago.21 “On reviewing the history of this species, there is one reflection that occurs with peculiar force, and should be constantly borne in mind by persons interested in the domestication of animals. The Rein Deer is one of those few domestic creatures which are known to exist in a state of aboriginal freedom; and it may well be asked, that if we knew it only as the prey of the N. American Indians, would not that person be deemed a visionary who should suppose that it might be tamed, milked, driven in harness, & thus brought to supply the place of all other domestic cattle to the inhabitants of the arctic wilds? He would assuredly be told, that the Deer family, as a group, are not adapted for domestication & servitude”, &c &c; & then I go on to suppose the probable fate of the Eland of S. Africa, & to write about the qualities, products, and properties developed by domestication, instancing the heavy dray-horse as one artificial animal, assuming the fleece of the sheep has been developed by domestication & so on—
Are the humped Camels & tropical cattle species or normal or abnormal varieties ? Are they merely analogous to the fat-rumped Sheep or otherwise? According to Buffon, the humps & the callosities, &c of the Camel are the results & badges that it bears of its long servitude; an opinion which would scarcely be backed by anyone now! In the ratio of its deviation from the ordinary ruminant type, so much the more conspicuous become the manifold adaptations of the Camel bearing direct reference to its natural mode of life & peculiar natural abode. Notwithstanding, however, those very special adaptations to the arid & sandy level, man has accustomed the Camel to traverse mountains (as in Socotra, vide Wellstead,22 —also in Teneriffe, &c), & the 2-humped species or the frontius of China & Tibet; and even rears the 1-humped belly-deep in water, at the mouth of the Indus for instance (vide Postans).23 We must cease to regard the Camel as the very type of a torrid region, now that we know that the two-humped species is about the reverse! Enough this about Camels. The permanence of every essential character in all the races of them, & the inconsiderable differences among those races, (which relate chiefly or wholly to their being more or less massive in conformation, heavy, or fleet & light, (as the Dromedaries of both species, from [CHARACTERS], tend to indicate that they have not been materially altered by domestication, or those various races would scarcely shew so great an amount of uniformity.
About the humped cattle, naturalists are still at loggerheads, & persist in continuing so; many seeming to regard them as about equally abnormal and artificial with the fat-tailed Sheep. Now I maintain (as you know) that they are as good & distinct a species as the Knobbed Goose, which is somewhat of an analogue among birds; & that neither of these has been essentially modified by domestication. The wild Gaour of India (Bos gaurus), which is the most gigantic of all existing bovine animals, has a small hump anterior to the extraordinarily long spinal apophyses (at least the bulls have, & the cows & oxen have but a small hump in the domestic species); & we have therefore this analogy of a genuine wild Bos, to shew that the hump is not necessarily the result of domestication. Mem. The frolicsome calves of the humped cattle are very commonly seen skipping about with the tail raised & curved down over the the back; older cattle too, occasionally— I donot remember this of European calves [DIAGRAM WITHIN TEXT] It has an odd appearance, & is thus held all the while they are running.24 The very early stage of fœtal life at which the hump & other peculiarities are conspicuously shewn, and the more advanced development of the teeth at birth, are other most important arguments; and remember that the hump is not a mere accumulation of fat, but contains much muscle attached to the spinal processes,—whence salted it is here a favorite viand, & is elsewhere sufficiently renowned under the erroneous name of “Buffalo’s hump” (a Buffalo, or a Bison, having nothing of the kind). Now a fœtal doomba (fat-tailed or fat-rumped Sheep) I have never seen. But as the fleshy hump is most developed in the adult bull, so is the fat behind of an old ram. (Among the Hottentots the fat behind is most developed in the gentle sex). One however I hold to be a typical structure, while the other is an abnormity or deformity. And, after all, it is only one of so very many distinctions which characterize (as I suspect) the Bos indicus wherever found, throughout its vast range of distribution in Asia & Africa, & in every subordinate race or variety; & where have the humpless races displayed so much as a tendency to assume any one of the following marked peculiarities of the humped cattle? The shorter body & abrupt droop towards the tail, peculiarly neat limbs, narrow pointed ears, large full expressive eye, dewlap coming from the chin, normal direction of the horns, & the grunting voice, (so very different from the bellowing of the bull & lowing of the ox & cow of the other),—also the indifference to the fiercest sun, & their never entering the water to realize the pretty word-picture in Thompson’s ‘Summer’—“Some ruminating lie, some bending sip the circling surface”, &c25 What more can be required to characterize it as a peculiar species? Why the advocates of the opposite opinion can adduce only the prolificacy of the hybrids, The late Ld Derby assured me that the small Muntjac Deer of China (Styloceros Reevesii bred freely with other Muntjacs, & that the progeny was equally prolific; whence the stock of different Muntjacs at Knowsley had become confusedly blended.26 which with me does not outweigh every other consideration. Of both there are many subordinate races, all true (I think it will be found) to the many distinctive characters of each species, but nought intermediate, excepting manifest & undoubted hybrids. The immensely large Hurriana cattle (of N. India), reared as ordinance cattle in the Company’s studs, with drooping ears & excessively developed dewlap & preputial skin, This shews conspicuously in the females! Who have [besides] their own præputium clitoridis.! &c, are doubtless an accidental race originally, improved by centuries of careful breeding. The so called Brahminy bulls exhibited in London illustrate this race: but, properly speaking, a Brahminy bull is a consecrated bull of any race. The dwarf cattle (Gyna, m. Gyni, female) do not reproduce dwarfs like themselves! I suspect there is even a hybrid race in China, analogous to the hybrid Geese of India; but we want more information about the Chinese cattle. In the S. of China I believe that Buffalo are chiefly (if not exclusively) employed. It is worthy of notice that the humped cattle have never been introduced (beyond here & there, perhaps, an individual or so, rarely,) in America; & consequently they have not gone wild there, as they have in Oudh; but they are better adapted than the other for the hot regions of America, & also of Australia. The Buffalo would also thrive along the banks of the great rivers of tropical America; but running wild would become rather a nuisance than otherwise. The Rein Deer are said to have become a nuisance in Iceland; depriving the few cows of their pasture: but rearing cows in Iceland for profit must be like attempting the same thing with Rein Deer in England or France; so why not rather domesticate & cultivate the race whose adaptations suit it to the climate?
I have just learned that the humped cattle have not yet been introduced into Borneo, but that in the S. regions of that island, a humpless race exists, similar to the Spanish cattle, & doubtless introduced by the Spaniards in former days! In Burma the humped cattle are small compact animals, rarely of the greyish-white colour predominant among those of India, but generally deep brown or black. The Ceylon cattle would seem to correspond. There is no peculiar breed of domestic fowls in Borneo; but the fowls of that country would seem to approximate the ordinary Bengal race, & are small, not feather-legged, & lay very small eggs. In general, I am told, they are somewhat peculiarly speckled.
The Indian hybrid race of Geese have been introduced into Burma; & as a matter of course now, they are not unfrequently taken there. There is no part of the world in which the domestic animals more require studying, than the vast Austral-Asian Archipelago.
Among the nations of S. Asia the Elephant is the type of strength; & what name do you suppose the natives of Bengal have given to the engine of a railway train? They call it the Pogla Hatti, or ‘Mad Elephant’! This name seems to have become current—
My new species of Orang, Pithecus curtus, is one of the most distinct of the lot—27 So Owen’s argument of the specifical unity of mankind, as presumed from the supposed fact of the gradual diminution of the number of species of the higher Apes, in proportion as they approximate the human type, is not good for much.28 We have now 3 species of Chimpanzee, and 5 of Orang-utan; & how little do we yet know of the zoology of the interior of tropical Africa, where more species of Chimpanzee may be reasonably expected. The Hippopotamus liberiensis, not larger than a good-sized Hog, is quite a recent discovery, though the animal is common in the settlement of Liberia 100 miles or so from the coast.
Within the last 5 or 6 years, the Achatina perdix (a large snail superabundantly common & a complete nuisance in Mauritius & Bourbon) has been introduced here from a single pair which I myself saw. They were brought from the Mauritius by Benson, the well known conchologist;29 & my friend Robt Frith30 allowed them to multiply in his father’s garden. They now swarm all over the neighbourhood. As the sexes of Snails are hermaphrodite, & this species is exceedingly prolific, the multiplication becomes proportionately rapid, but is quite wondrous in the present instance. Previously we had no land-snail in Lower Bengal bigger than the little Bulimus bengalensis, which is not half the size of the British Helix nemoralis; but this was no more due to climate than the non-existence of large Ruminantia in S. America. The Achatina perdix will doubtless spread, & rapidly, over the whole country; and I am not aware of any species enemy that it has encountered as yet.
I have been dipping into Lyell’s second volume, & find that I shall have not a little to say. Some 18 years have passed since I studied the ‘Principles’; but I did so with intense interest, & carefully read the whole work twice over; and I doubt if any salient fact has escaped my memory. From that time to the present I have felt that revision was necessary.31 Of course I have the utmost respect for Sir C. Lyell; & his arguments are no doubt sound in the main. His conclusions are legitimately deduced from his premises; but the latter, or his assumed data (on the authority of others duly quoted), are erroneous in very many instances; & I shall have to devote a long letter to their rectification so far as my knowledge of the facts enables me to controvert the published statements. In this somewhat ungracious task I do not wish to appear prominently; but truth is what we seek, & the establishment of it is the more important in proportion to the high scientific rank of the authority we presume to call in question.
Origin of domestic varieties. EB ascribes "abnormal" variations to man’s propagation of casual monstrosities; believes "normal" variations, e.g. European races of cattle, are a consequence of man’s selecting the choicest specimens. Gives examples of "abnormal" variations; they give rise to features that have no counterpart among possible wild progenitors. Divides domestic animals into those whose origin is known and those whose origin is unknown. Considers that the wild progenitors of nearly all domestic birds are known. Fowls and pigeons show many varieties but if propagated abnormalities are ignored each group can be seen to be variations of a single species, the ancestors of which can be recognised without difficulty. Discusses varieties and ancestry of the domestic fowl. Variation in the wild; the ruff shows exceptional variability; other species of birds show variability in size of individuals. Remarks that markings sometimes vary on different sides of the same animal. Comments on the want of regularity in leaf and petal patterns of some plants. Discusses domestic varieties of reindeer and camels. Origin of humped cattle. Reports the rapid spread of a snail in lower Bengal that was introduced as a single pair five or six years previously.
[CD’s notes are an abstract of part of this memorandum. Memorandum originally enclosed with 1760.]
- breeding (artificial)
- constant varieties, races
- flowers and buds
- geographical distribution
- historical time
- human intervention
- introduced forms
- number, increase and decrease
- plant physiology
- species, speciation
- type and morphology
- wild vs domestic forms
Please cite as
Darwin Correspondence Project, “Letter no. 1761,” accessed on 25 August 2016, http://www.darwinproject.ac.uk/DCP-LETT-1761