I 4 8 household bacteriology 
usually due to the handling or rubbing of the little 
wound by dirty persons, against the warning of the 
physician. 
Largely as the result of this form of preventive 
inoculation, smallpox is no longer to be seriously 
dreaded. In fact, in the graphic charts which the 
statisticians make out to show the relative frequency 
of various diseases, the lines showing smallpox are 
so short that you can hardly see them; while it is those 
representing tuberculosis, pneumonia and other dis¬ 
eases of the respiratory system which stretch in most 
disquieting fashion across the page. 
HYDROPHOBIA 
Rabies, or hydrophobia, is one of the most dreaded 
of human maladies, and one whose victims in former 
times no medical skill could save. It is an infectious 
disease, though the micro-organism inducing it is still 
undiscovered. Hydrophobia is commonly acquired by 
man through the bites of rabic animals, in this country 
most frequently the dog. The unknown infectious 
agent is present in the saliva of affected animals. It 
travels along the nerve trunks from the site of the 
bite to the central nervous system, where it especially 
concentrates itself. 
Pasteur, the great master in the solution of knotty 
problems relating to bacteria and immunity, spent 
many toilsome and harassing years in the study of 
the rabic virus and in attempts to devise an effective 
method of protection. He found at last that, although 
he could not isolate the microbe, he could transmit 
