REE SALES HP 
ur ON ANIMAL LIFE ~ 99 
isms are of vital importance. Many diseases 
are now known, and others suspected, to be 
entirely due to Bacteria and other minute 
forms of life (Microbes), which multiply in- - 
credibly, and either destroy their victims, or 
after a while diminish again in numbers. We 
live indeed in a cloud of Bacteria. At the 
observatory of Montsouris at Paris it has 
been calculated that there are about 80 in 
each cubic meter of air. Elsewhere, however, 
they are much more numerous. Pasteur’s re- 
searches on the Silkworm disease led him to 
the discovery of Bacterium anthracis, the 
cause of splenic fever. Microbes are present 
in persons suffering from cholera, typhus, 
whooping-cough, measles, hydrophobia, etc., 
but as to their history and connection with 
disease we have yet much to learn. It is 
fortunate, indeed, that they do not all at- 
tack us. 
In surgical cases, again, the danger of com- 
pound fractures and mortification of wounds 
has been found to be mainly due to the pres- 
ence of microscopic organisms; and Lister, by 
his antiseptic treatment which destroys these 
