148 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 



