548 GENERAL BIOLOGY — A REVIEW AND SUMMARY 
The United States has its department of health that tries 
to prevent diseases from other countries from entering our 
land through ports and harbors. More and more the dis¬ 
coveries of medical men and biologists are making people 
healthier, and it is our duty to acquaint ourselves with the 
new discoveries bearing upon matters of health. 
Review the following: sections 29, 35, 160, 182; and 
figures 45-47. 
418. Departments of Agriculture and Forestry. — Aside 
from the health work of the states and the national govern¬ 
ment we find them active in many other fields. Among 
their other important functions is that which deals with 
crops and their enemies, new ways of treating the soil, con¬ 
trol of seed testing, analysis of various fertilizers, and many 
other kinds of work that have to do with farming and for¬ 
estry. 
There are so many other uses of forests than simply fur¬ 
nishing lumber that certain forests are not used for lumber 
at all. The regular flow of some rivers and spring streams is 
due to the permanence of the forests on their watershed. 
Take away the forests entirely and many springs would not 
furnish water in dry seasons, many streams would dry up, 
and fish would die. 
The forests are important directly and indirectly to many 
people. Recently the people of the State of New York 
voted to buy thousands of acres in the Adirondacks in order 
that all the people might have some of the benefits that 
come from forests. The reclaiming of arid lands and making 
them productive in the Western States is another govern¬ 
ment activity that has to do with agriculture and the in¬ 
creased production of food crops. 
Review the following: section 182; and chapters XXVII, 
XXIX. 
419. Plant and Animal Improvement. — We are accus¬ 
tomed now and then to hear discussions that give an idea 
