THE DESCENT OB ORIGIN OF MAN 2il 



a single pair, or even from a single individual possessing 

 gome new character; but most of our races have been formed, 

 not intentionally from a selected pair, but unconsciously by 

 the preservation of many individuals which have varied, 

 however slightly, in some useful or desired manner. If 

 in one country stronger and heavier horses, and in another 

 country lighter and fleeter ones, were habitually preferred, 

 we may feel sure that two distinct sub-breeds would be pro- 

 duced in the course of time, without any one pair having 

 been separated and bred from, in either country. Many 

 races have been thus formed, and their manner of formation 

 is closely analogous to that of natural species. We know, 

 also, that the horses taken to the Falkland Islands have, 

 during successive generations, become smaller and weaker, 

 while those which have run wild on the Pampas have ac- 

 quired larger and coarser heads; and such changes are mani- 

 festly due, not to any one pair, but to all the individuals 

 having been subjected to the same conditions, aided, per- 

 haps, by the principle of reversion. The new sub-breeds in 

 such cases are not descended from any single pair, but from 

 many individuals which have varied in different degrees, 

 but in the same general manner; and we may conclude that 

 the races of man have been similarly produced, the modifica- 

 tions being either the direct result of exposure to different 

 conditions, or the indirect result of some form of selection. 

 But to this latter subject we shall presently return. 



On the Extinction of the Races of Man. — The partial or 

 complete extinction of many races and sub-races of man 

 is historically known. Humboldt saw in South America a 

 parrot which was the sole living creature that could speak 

 a word of the language of a lost tribe. '^ Ancient monuments 

 and stone implements found in all parts of the world, about 

 which no tradition has been preserved by the present inhab- 

 itants, indicate much extinction. Some small and brokea 

 tribes, remnants of former races, still survive in isolated and 

 generally mountainous districts. In Europe the ancient 



Descent— Vol. I. — 11 



