1312 



VARIETIES OF MANKIND. 



occasionally produce another curious variety, 

 characterised by the entire absence of hair ; 

 these naked-skinned oxen, which are called 

 " calongos," are, like the pelones, unable to 

 bear a cold climate, and are very delicate and 

 weak. Another remarkable fact, relative to 

 the oxen of South America, is recorded by 

 M. Roulin. In Columbia, the practice of 

 milking cows was laid aside, owing to the 

 great extent of the farms and other circum- 

 stances. In a few generations, the natural 

 structure of the parts and the natural state 

 of the function have been restored ; the se- 

 cretion of milk taking place only so long 

 as the calf remains with the mother, and 

 ceasing if it dies or is removed. Hence we 

 have a valuable confirmation of the belief 

 previously entertained, that the continued 

 production of milk by the European breeds 

 of cows is a modified function in the animal 

 economy, originating in an artificial habit 

 kept up through many generations, and depend- 

 ent upon a modification of structure which 

 that habit has been the means of inducing. 



That the various breeds of sheep at present 

 domesticated in Europe, have had a common 

 origin, is not doubted by any zoologist, not- 

 withstanding the differences in their stature 

 and proportions, the texture and colour of 

 their wool, the presence or absence of horns, 

 &c. The most marked deviation from the 

 usual type is presented by a breed of Spanish 

 sheep, distinguished by the length and 

 straightness of the hair, and by the length and 

 spiral twist of the horns. Various breeds 

 are found in Asia and Africa, as to whose 

 specific unity with each other, and with Eu- 

 ropean sheep, zoologists are not agreed. We 

 have a remarkable example of climatic varia- 

 tion, however, in the fact, that in the races 

 spread through Persia, Tartary, and China, 

 the tail seems replaced by a double spherical 

 mass of fat, which forms a most awkward 

 excrescence on the rump, and is nearly desti- 

 tute of hair; whilst these sheep, transferred to 

 the cold, dry pastures of Siberia, are affirmed 

 by Ermann to lose this peculiar conformation 

 in the course of a few generations. The 

 sheep of Syria and Barbary, on the other 

 hand, have an accumulation of fat in the tail 

 itself, which is long, and sometimes attains a 

 weight of from seventy to one hundred pounds. 

 It is a curious and very significant fact, that 

 the sheep of the Cape of Good Hope, which 

 are descended from the European stocks, 

 should exhibit the same tendency to the 

 accumulation of fat about the rump, as is 

 seen in the human races indigenous to that 

 region. The sheep which were transported 

 into South America by the Spaniards, have 

 not multiplied so extensively as the oxen and 

 swine; and from their more limited diffusion, 

 we find, as might be expected, that they ex- 

 hibit but a comparatively slight amount of 

 variation. The remarkable change in the 



depends upon the adaptation between the constitu- 

 tion of the several races and the climates in which 

 we find them, is deficient in solidity of foundation. 



character of the hair, presented by the sheep 

 in the West Indies has been already referred 

 to. Among sheep, as among other do- 

 mesticated animals, new races are continually 

 being produced by breeders, not merely by 

 crossing or intermixing races already con- 

 stituted and well known, but also by taking 

 advantage of peculiarities which occasion- 

 ally present themselves spontaneously, and 

 using means to perpetuate these. The fol- 

 lowing is one of the most curious examples 

 of this kind upon record. In the year 1791, 

 a ewe on the farm of Seth Wright, in the 

 state of Massachusetts, gave birth to a male 

 lamb, which, without any known cause, had a 

 longer body and shorter legs than the rest of 

 the breed ; the joints also were peculiarly 

 formed, and the fore-legs crooked. The con- 

 formation of this animal rendering it unable 

 to leap over fences, it was thought desirable to 

 endeavour to propagate its peculiarities ; and 

 accordingly when it was fit for procreation, 

 several ewes were impregnated by it. Out of 

 the lambs first produced, only two presented 

 the same peculiarities ; more were obtained 

 in subsequent years ; and when they became 

 capable of breeding with each other, the new 

 race was completely established ; its distinc- 

 tive characters being uniformly presented when 

 both parents possessed them, but tending to 

 disappear when the sheep of the " ancon" or 

 "otter" breed (as it is called) were allowed 

 to breed with those of the ordinary type.* 

 This fact, as we shall hereafter see, has an 

 important bearing on the question of the 

 spontaneous origination of permanent varieties, 

 in the human or any other species that is 

 disposed to undergo occasional modifications ; 

 which modifications, under ordinary circum- 

 stances, disappear as often as they recur. 

 Thus it is not uncommon to meet with fami- 

 lies distinguished by the possession of some 

 peculiarity of feature, or by some well marked 

 departure from the ordinary conformation, 

 such as the possession of six fingers on each 

 hand and six toes on each foot. If such were 

 to intermarry exclusively with one another, 

 there can be no reasonable doubt that the 

 children would invariably exhibit the same 

 peculiarity ; and that the six-fingered race, 

 which now tends, whenever it is originated, 

 to merge in the prevailing five-fingered type, 

 would then become permanent. When it is 

 considered that the influence of a scanty 

 population, in the early ages of the world, 

 by isolating different families from each other, 



and 



causing inter-marriages amongst even 



very near relatives, would have been precisely 

 the same with that which is now exercised by 

 the breeders of animals, we see one reason 

 why the varieties which then arose should 

 have had a much greater tendency to per- 

 petuation, than those which now occasionally 

 present themselves. 



In regard to the horse, it will be sufficient 

 to observe that no zoologist has ever ex- 



* See Col. Hutchinson's Memoir 'in the Philo- 

 sophical Transactions for 1813. 



