230 SELECTION. Chap. XXI 



doubt that many parts of the organisation, to which man has 

 attended, have been thus modified to a greater degree than 

 the corresponding parts in the natural species of the same 

 genera or even families. We see this in the form and size 

 of our light and heavy dogs or horses, — in the beak and many 

 other characters of our pigeons,— in the size and quality of 

 many fruits, — in comparison with the species belonging to 

 the same natural groups. 



Time is an important element in the formation of our 

 domestic races, as it permits innumerable individuals to be 

 born, and these when exposed to diversified conditions are 

 rendered variable. Methodical selection has been occasionally 

 practised from an ancient period to the present day, even by 

 semi-civilised people, and during former times will have pro- 

 duced some effect. Unconscious selection will have been still 

 more effective; for during a lengthened period the more 

 valuable individual animals will occasionally have been 

 saved, and the less valuable neglected. In the course of time, 

 different varieties, especially in the less civilised countries, 

 will also have been more or less modified through natural 

 selection. It is generally believed, though on this head we 

 have little or no evidence, that new characters in time be- 

 come fixed ; and after having long remained fixed it seems pos- 

 sible that under new conditions they might again be rendered 

 variable. 



How great the lapse of time has been since man first do- 

 mesticated animals and cultivated plants, we begin dimly to 

 see. When the lake-dwellings of Switzerland were inhabited 

 during the Neolithic period, several aiiimals were already 

 domesticated and various plants cultivated. The science of 

 language tells us that the art of ploughing and sowing the 

 land was followed, and the chief animals had been already 

 domesticated, at an epoch so immensely remote, that the 

 Sanskrit, Greek, Latin, Gothic, Celtic, and Sclavonic languages 

 had not as yet diverged from their common parent-tongue. 69 



It is scarcely possible to overrate the effects of selection 

 occasionally carried on in various ways and places during 

 thousands of generations. All that we know, and, in a still 

 6 . 9 Max Milller, 'Science of Language,' 1861, p. 223. 



