2 INTRODUCTION 
indirectly dependent upon plants. The earliest "botan- 
ical" interests were naturally in plants as food. But 
it must have been discovered early in the history of man- 
kind that some plants were not only not good to eat, but 
positively poisonous, causing sickness or even death; 
while others produced marked physiological effects, acting 
some on one part of the body, some on another, like medi- 
cine, and thus was early developed the study of plants 
in order to ascertain their medicinal properties, and 
their value in the treatment of diseases. This interest is 
still reflected in the Spanish name for a drug store 
botica. 
2. Relation of Plants to Man. Thus we see that the 
primary reason for our being interested in plants at all 
was because they are intimately related to our physical 
existence and well-being. As civilization advanced, 
other uses for plants and plant products were discovered, 
and thus other reasons for being interested in them. 
They furnish all the wood of the world, and one has only 
to consider for a moment how absolutely dependent we 
are on wood, to realize still more vividly the intimate 
relation between the life of plants and that of man him- 
self. Our houses and furniture are of wood, our food 
(the product of plants) is shipped in wooden boxes, 
crates, and barrels, over rails supported by wooden ties; 
most of the paper in use is made of wood pulp, and 
innumerable articles in daily use lead pencils, tool 
handles, many musical instruments, et cetera are made 
largely of wood. Surely, it would be rather strange 
if we did not have some interest, at least, in objects 
so closely related to our daily lives, our welfare, and our 
happiness. 
