HISTORY OF ORGANIC EVOLUTION—COULTER 325 
that may vary with the investigator, but which will be checked up 
by further investigation. The progressive advance of species, how- 
ever, is still within the region of inference. It is something like 
the difference between the tracks in a switch yard and the main line. 
We have succeeded in investigating the switching, but the through 
trains are baflling. 
PRACTICAL RESULTS 
I wish now to call attention to the practical results that the study 
of evolution has made possible. The experimental study of evolu- 
tion, leading to the development of the science of genetics, resulting 
in increasing knowledge of the laws of inheritance, has led to prac- 
tical results which the public in general do not appreciate. I shall 
select only one illustration from very many, but it will serve to in- 
dicate the sort of service the study of evolution has rendered in a 
practical way, in addition to its service in the advancement of knowl- 
edge. I have selected the revolution in agriculture. It seems a far 
ery from speculations concerning evolution to a revolution in agri- 
culture, but the continuity is unbroken. Speculation led to observa- 
tion; observation led to experimentation; experimentation resulted 
in discovering Jaws of inheritance; and the application of these laws 
has enabled us to handle plants and animals in a way that was 
never dreamed of before. It is a good illustration of the fact 
that there is no sharp dividing line between what are called pure 
science and applied science, for pure science may prove immensely 
practical. 
A very brief statement will illustrate the agricultural results in 
the application of our knowledge of inheritance. 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 pro- 
duction. The statement was made that during the 10 years pre- 
ceding the great war our population had increased 20 per cent, and 
our food production about 1 per cent. It was certainly an alarm- 
ing 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 environment, destruction by 
drought, and destruction by disease. The same races were being 
cultivated everywhere, and only in certain places was the maximum 
result obtained. A study of races of crop plants throughout the 
world, and of the environment necessary for maximum yield, re- 
sulted in such an adjustment of crops to conditions that total food 
production was enormously increased. 
