480 MAN CONTROLS HIS ENVIRONMENT FOR HEALTH 



be seen with the most powerful microscope. The virus used for 

 inoculation probably contains the organisms which cause cowpox, 

 which is a weakened smallpox organism. Therefore when vacci- 

 nation " takes," the body has been stimulated by the virus to 

 produce its own antibodies. These antibodies make the body 

 actively immune to the disease. 



Smallpox has been in the past a great scourge ; 90 out of every 

 100 persons in Europe used to have it. As late as 1898, in Russia 



1921 1922 1923 192419251926192719281929 1930 I 1921 1922 1923 1924 1925 1926 1927 1929 1929 1930 



deaths 000200001 o deaths 20 l .56 5B 236 5 2 10 7 



Massachusetts 



Cases. « 2 6 12 3 4 2 19 273 2 cases 

 repor ted . ■ 



1921 192219231924192519261927192819291930 I 1921 1922 1923 192419251926 192?192S1929 1930 



Massachusetts has a law requiring all persons to be vaccinated against smallpox infection. 

 California, at one time, had such a law, but repealed it. Notice the number of cases and deaths 

 from smallpox in California as compared with Massachusetts from 1922 to 1930. 



over 50,000 persons lost their lives from this disease in a year. 

 In some places smallpox has been brought under absolute control 

 by vaccination, though in other places, unfortunately, there are 

 outbreaks, due to the fact that some people do not believe in 

 vaccination. 



Rabies, or hydrophobia. Rabies (ra/bi-ez), which is caused by 

 a filterable virus, is communicated in the saliva from one dog to 

 another by biting. It is also transmitted to man by the bite of an 

 infected animal. The great French bacteriologist, Louis Pasteur, 

 discovered a method of treating this disease which is a success if 

 begun soon after the person has been bitten by the infected 

 animal. Here again the treatment is based upon the inocu- 

 lation of the patient with a weakened organism which causes 



