THE MICROBES OF HUMAN DISEASES, 171 
the reason why these men seem to enjoy an immunity 
from most contagious diseases. 
People are too much disposed, when an epidemic 
is prevalent, to accuse the privies, of which the 
emanations are, under ordinary circumstances, only 
offensive to the smell. When these places, as well as 
the sewers, are properly constructed, they present no 
danger. But it is necessary that there should be 
a sufficient flow of water in both to cover the solid 
matter. We know, in fact, that if microbes are present, 
they only become dangerous when dry enough to float 
in the air. 
In an epidemic of typhoid fever, for instance, the 
soiled body and bed linen of the patient are much more 
dangerous than the privies, in which, however, there 
is a much larger number of microbes. The linen, 
therefore, as well as the contaminated rooms and 
furniture, should be immediately disinfected in the 
mode prescribed by sanitary authorities. 
The system of directing everything to the sewer, 
which is now universally applied to large towns, and 
which has encountered much opposition, is certainly 
excellent when properly understood and applied. The 
cesspools, as well as the cemeteries, ought to be as 
remote as possible from the houses of the living. It 
is as much opposed to public health to retain cesspools 
which are gradually filled in the course of years, in 
the midst of a town, as to have intramural cemeteries. 
Everything should be carried off by the sewer, pro- 
