n] OF EVOLUTION 9 



How early the principles of variation and heredity, 

 and even the possibility of improving breeds by 

 selection, must have been appreciated by early men 

 is illustrated by the old story of the way in which the 

 wily Jacob made an attempt however futile were the 

 means he adopted to cheat his employer Laban 4 . 



Yet, in spite of observed tendencies to variation 

 among animals and plants, early man must have been 

 convinced of the existence of distinct kinds ('species') 

 in both the vegetable and animal worlds ; he recog- 

 nised that plants of definite kinds yielded particular 

 fruits, and that different kinds of animals did not 

 breed promiscuously with one another, but that, 

 pairing each with its own kind, all gave rise to like 

 offspring, and thus arose the idea of distinct 'species' 

 of plants and animals. 



It must be remembered, however, that for a long 

 time * the world ' was believed to be limited to a few 

 districts surrounding the Eastern Mediterranean, and 

 the kinds or 'species' of animals and plants were 

 supposed to number a few scores or at most hundreds. 

 This being the case, the sudden stocking of 'the 

 world' with its complement of animals and plants 

 would be thought a comparatively simple operation, 

 and the violent destruction of the whole a scarcely 

 serious result Even the possibility of the preserva- 

 tion of pairs of all the different species, in a ship of 

 moderate dimensions, was oue that was easily enter- 



