206 THE DESCENT OF MAN. 



notice, namely, whether, as is sometimes assumed, each 

 sub-species or race of man has sprung from a single pair of 

 progenitors. With our domestic animals a new race can 

 readily be formed by carefully matching the varying off- 

 spring from a single pair, or even from a single individual 

 possessing some 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 produced in the course of time, with- 

 out 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 acquired larger and coarser heads; 

 and such changes are manifestly due, not to any one pair, 

 but to all the individuals having been subjected to the 

 same conditions, aided, perhaps, by the principle of rever- 

 sion. 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 modifications 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 01 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 

 inhabitants, indicate much extinction. Some small and 

 broken tribes, remnants of former races, still survive in 

 isolated and generally mountainous districts. In Europe 



