DOMESTICATION OF ANIMALS 259 



dog, 1 the pig, and the fowl. Cattle may also have 

 been tamed from a stock which lived in tropical 

 forests, like the Indian bison and the buffalo of 

 the present day. To domesticate animals of such 

 large size was a great achievement : cattle not 

 only supplied man with milk and flesh, but lent 

 their strength to cultivate with the plough, and 

 we can understand how they came to be regarded 

 as wealth par excellence, and were accepted as the 

 symbols of private property. Sheep and goats 

 would be added by tribes which left the plains 

 for the mountains : the horse, the camel, and 

 the ass would be met by the wanderers as, in their 

 northward course, they emerged upon the plains 

 of Central Asia and spread towards Egypt. The 

 strange conditions of domesticated life stimulated 

 variations in these captive animals : peculiarities 

 that arose were fixed by breeding, so that in the 

 course of time they departed very widely from 

 their ancestors in colour, form, and size. But, 

 if permitted to regain their freedom, they will 

 still revert to their original type. 



Not less momentous was the discovery that 

 man could intervene between Nature and her 

 plants, making them to grow in uniform crops 

 instead of sporadically, as in the jungle, and 

 improving the quality and quantity of their pro- 

 duce. So long a period has elapsed since the 

 principal food plants were reclaimed from the 

 wilderness that the ancestors of many of them 



1 Upon the companionship of man and his brute associates 

 certain parasites have built up a very peculiar course of livelihood. 

 The tape-worm of man passes its embryonic stages, as a trichina, 

 in the tissues of the pig, whence it passes to man by the eating of 

 pig's flesh. It is disconcerting to learn that a tape- worm of the 

 dog's occurs as a trichina in human tissues. There are traditions 

 of peoples who maintained packs of hounds as cemeteries for the 

 disposal of their dead ; and we may conjecture that in the days of 

 primaeval darkness the dog was drawn to man by this gruesome 

 office. 



