136 PLANTS AND MAN 
look for information as to the time and place and 
nature of man’s conquest of the surface of the globe. 
At the period of the earliest: human civilizations, such 
as those of Egypt and Mesopotamia, the domestica- 
tion of plants and animals had already reached an 
advanced stage. Its origin lies far behind the historic 
period. We can picture in imagination the time when 
in all inhabited parts of the globe man wandered with 
no fixed abode, seeking food when he was hungry, 
and making no provision for the morrow. Residence 
in a spot which afforded a valued supply of food, such 
as an abundance of buckwheat or millet or dates or 
bread-fruit, might lead to a desire to encourage the 
growth of such useful plants by protecting them and 
their offspring; following on which might arise the 
practice of assisting their growth, and thus eventually 
of cultivating them. Selection of the most productive 
strains would gradually follow, and barter would 
cause the spread of useful plants over wider and 
wider areas. We can picture development from such 
rude beginnings into the regular cultivation of the 
soil and the enclosing of the cultivated areas for their 
protection. It is clear that such practices would not 
readily arise among nomadic tribes, nor among those 
inhabiting forest regions where the ground was 
densely covered by trees. An abundance of animal 
food would produce a race of hunters rather than of 
tillers of the soil; and as for forest regions, they are 
unsuitable for human development; forest races have 
never been pioneers of civilization. Before agri- 
culture—indeed, before civilization in any form— 
could make much progress, a settled life was 
necessary, free from migrations in search of food or 
