42 
VERTEBRATA. 
known to the ancients, and large breeds of them are fonnd in Hnngary and Sweden, In some, 
also, the hoof is divided into five clefts. In Guinea, they have long- ears couched upon the back ; 
in China, a large pendent belly and very short legs ; at Cape Verd and other places, very large 
curved tusks. Thus,- then, in one species Ave find changes even greater than those which occui- 
among men ; and as to the most important, Bhimenbach says that the whole difference between 
the cranium of the negro and that of a European is by no means greater than that which exists 
between the cranium of the wild-boar and that of the domestic swine. An examination of the 
difi'erent breeds of sheep, horses, oxen, goats, cats, rabbits, doves, and still more of the domestic 
fowl, would in like manner show that all these species, even while under observation, are subject 
to greater variations than are found in the difi'erent races of men. The various breeds of dogs are 
believed to have all descended from one parent stock ; yet what greater diversity is there in the 
tribes of mankind than in these animals, from the robust and adventurous Newfoundland doo- to 
the soft and silken lap-dog? ' 
In respect of color, a perfect analogy holds between the varieties of domestic animals and those 
of men. In all those enumerated above, examples occur of the meianocomous, leucous, and 
xanthous varieties springing up casually or existing cons^-antly in particular breeds. Thus even 
in England the cattle of difi'erent counties may be recognized by their color as well as by their 
forms. Azara remarks of the oxen and horses of Paraguay, where both species have run wild 
and multipHed very rapidly, that while all those that are domesticated vary considerably in color, 
those that are wild have all the same color ; — the horses a chestnut or bay-brown ; the oxen red- 
dish-brown on the back, and black on the rest of the body. 
This analogy between the variations to which domesticated, and more rarely wild animals, are 
subject, and those which are observed in men, is a strong argument for the unity of the human 
species. Another, which possesses much weight, is drawn from the propagation of the several 
races. It is well known that among all other animals, the hybrid productions of parents of difi'er- 
ent species are either quite barren, or so little prolific that they soon become extinct, and that an 
intermediate race cannot be maintained even to the second generation without a return to the 
pure blood of one or other parent. On the other hand, it is observed among domestic animals 
that the progeny of different varieties of the same species exceed in vigor, and are even more 
prolific than their parents ; so that intermediate races are apt very soon to become more numer- 
ous than the originals from whence they sprung. It is asserted that exactly the same principle 
holds in the human race. All nations, it is said, propagate together with equal facility, and it is 
contended that the progeny of parents of different nations have in many instances exceeded those 
from whom they sprung in vigor and in the tendency to multiplication. 
What may be the precise nature of the infiuences which have caused so much difference to 
exist between the individuals of the human race, Ave are unable to say ; but instances are con- 
stantly occurring which seem to show us how possible it is that all the varieties of human beings 
have occurred in a common family. It is remarked by high English authority, that " even among 
the races of our own island, Avhen exposed to circumstances which deprive them of their usual 
nutriment and means of developing the civiHzing instincts of mankind, we find that they sink in 
character, and become physically degraded to a level Avith races Avhose features at first sight are 
very far I'emoved. We need but to travel across the Irish Channel to see many groups of our 
Celtic fellow-subjects Avho have been reduced by famine and disease to a degraded condition 
closely bordering on that of these savages." 
Although the color of the skin and the character of the hair give so very decided an appearance 
to many of the races of man, yet, as before remarked, there are on record a great number of cases 
in Avhich individuals, with hair and skin of one color, have given birth to children with hair and 
skin of another color and character. Dr. Prichard mentions numerous instances of individuals 
with yelloAV hair and fair skin, among tribes Avith dark hair and skin ; and in the temperate regions 
of Asia, Avhole tribes, evidently descended from dark-colored races, present the light color. The 
Jews appear to have been originally a dark-skinned and Avoolly-haired race ; but it is Avell knoAvn 
that the Jcavs of Europe very frequently possess the characteristics of the lightest-colored races. 
On the other hand, Ave constantly see individuals born of white parents having Avoolly hair, a 
