8 SANITARY PRIVY. - 
human excreta endangers the health of a family, just as soil pollu- 
tion of a pasture by the droppings of animals eridangers the live 
stock. 
In order to prevent the evil effects of soil pollution from extending 
to his live stock, the farmer must resort to more or less expensive 
methods, such as purchase of additional pasture lands or burning 
the pasture. But since human beings, on account of their superior 
intelligence, can be taught to frequent an appointed place to deposit 
their excreta, it is possible (by the expenditure of a few dollars for 
a Sanitary privy) to prevent soil pollution with human excreta, 
thereby protecting the family, and enabling it to live year after year 
on the same premises (family pasture) without danger, at the same 
time saving doctors’ bills and avoiding unnecessary sickness and 
death. 
DISEASES SPREAD FROM MAN BY SOIL POLLUTION. 
It is especially the diseases caused by parasites (both animal and 
bacterial) of the intestine, lungs, liver, kidneys, and bladder that are 
spread by soil pollution. Some of these diseases are spread from 
human being to human being; others are spread from human beings 
to the farm animals. Therefore, in preventing soil pollution by per- 
sons, both families and live stock are protected. 
The proper disposal of human excreta is recognized by sanitarians 
as the most important measure needed to prevent the spread of 
typhoid fever, hookworm disease, the dysenteries, and certain other 
widely prevalent diseases. 
DISEASES SPREAD FROM MAN TO MAN. 
Some of the diseases which come under this heading are caused by 
microscopic parasites known as bacteria; others by animal parasites, 
which are considerably larger than the bacteria. 
BACTERIAL DISEASES, 
Among the most important diseases under this heading may be 
mentioned typhoid fever, dysentery and diarrhea (“summer com- 
plaint”’), and tuberculosis (‘‘ consumption”). 
Typhoid fever.—Every person who contracts typhoid fever does so 
because he has recently swallowed some typhoid germs that have been 
passed in the stools or urine of some other person, who either (as a 
patient) was suffering from typhoid or (as a “ carrier”) was carrying 
the germs without showing symptoms. 
The germs (bacilli) of typhoid fever are of very minute size, a 
gingle germ (bacillus) being only about zz49> of an inch in length 
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