THE DEPENDENCE OF MAN 9 
unlimited employment and skill, not only in design but in 
execution as well. 
When we regard facts such as these and consider the mul- 
titude of purposes to which wood is put, the use of pulp for 
paper, the flouring of grains, the carding and spinning of vege- 
table and animal fibers, then it is that we begin to realize how 
generally and how fully our domesticated animals and plants 
afford what might be called the raw materials of civilization. 
Medicinal properties of animals and plants. It is not only in 
health but also in disease that animals and plants serve our 
needs. Nearly all medicinal preparations are from some species 
of plant, and each has its characteristic action on some portion 
or portions of the body or its functions. 
Certain glands of animals, too, are coming to be much used 
in the preparation of medicines. If the thyroid gland of the 
child, for example, fails to develop, the mental faculties will be 
impaired; but the calamity can be averted by feeding the subject 
with the thyroid substance of the sheep. 
And so in countless ways our lives have come to be bound 
up with those of the animals and plants that we cultivate, and 
our ability to maintain our civilization and insure our continued 
happiness will depend very largely upon the success with which 
we can maintain these animal and plant assistants and cause 
them to minister to our good. 
The business of farming. The systematic and continued pro- 
duction of domesticated animals and plants, insuring a perpetual 
supply of their products, is the business of farming. Considered 
from the individual standpoint, we may like it or not according 
to our natural bent and our like or dislike of animals and the 
handling of crops, but looked at from the racial and economic 
standpoint, there is no more important work for the continued 
welfare of man than that of maintaining a continuous supply of 
plant and animal products. 
Nor is this task a simple one. The supply must be ample 
for an increasing population with increasing needs, although 
