EVOLUTION 179 



It had become evident, for example, that for various 

 reasons the ratio of increase in population was much 

 greater than the ratio of increase in food production. 

 The statement was made that during the ten years 

 preceding the great war our population had increased 

 20 per cent, and our food production about I per 

 cent. I cannot vouch for the accuracy of this state- 

 ment, but it illustrates the situation. It was certainly 

 an alarming outlook. Under these circumstances, 

 plant crops began to be studied from the standpoint 

 of genetics, and plant breeding became a science. 



The lack of crop production arose chiefly from three 

 causes, namely, lack of adaptation of crops to environ- 

 ment, destruction by drought, and destruction by 

 disease. The same races were being cultivated every- 

 where, and only in certain places was the maximum re- 

 sult obtained. A study of races of crop plants through- 

 out the world, and of the environment necessary for 

 maximum yield, resulted in such an adjustment of 

 crops to conditions that total food production was enor- 

 mously increased. The problem of drought is being 

 rapidly solved by the discovery or development of 

 drought resistant races, not only insuring against loss 

 from this cause, but also enormously increasing the 

 possible area of cultivation. The problem of disease 

 has been attacked in the same way, and disease resistant 

 races of most of the important crops have been devel- 

 oped, insuring against this loss. As a result, food pro- 

 duction is now beginning to overtake population, and 

 we may thank the persistent study of evolution for the 

 result. 



