262 



BACTERIA AND DISEASE 



300 



200 





some of the germs. From this it follows that if we know how 

 a given disease is communicated, we ma}^ protect ourselves from 

 it and aid the civic authorities in preventing its spread. 



Tuberculosis. — One of the diseases responsible for the greatest 

 number of deaths, perhaps one tenth of the total on the globe, is 

 tuberculosis. It is estimated that of all people ahve in the United 

 States to-day, 5,000,000 will die of this disease. Fisher estimates 

 that tuberculosis costs this country between $500,000,000 and 



81,000,000,000 a yesLY, by 

 its toU of death, loss of 

 work, maintenance of hos- 

 pitals, sanatoriums, etc. 

 But this disease is slowly 

 but surely being overcome. 

 It is believed that within 

 perhaps fifty years, with 

 the aid of good laws and 

 sanitary living, it might 

 become almost extinct. In 

 Xew York state the death 

 rate has decreased from 

 186.8 per 100,000 in 1900 

 to 87.8 in 1923, and equalh^ good records come from other parts of 

 the United States. 



Tuberculosis is caused by the growth of bacteria,, called the 

 tubercle hacilU, within the lungs or other tissues of the human body. 

 In the lungs they form httle tubercles full of germs, which close up 

 the dehcate air passages, while in other tissues they may cause 

 hip-joint disease, scrofula, lupus, and other diseases, depending 

 on the part of the bodj^ they attack. Tuberculosis may be con- 

 tracted by taking in bacteria through the mouth from people who 

 have the disease, or possibly by drinking milk from tubercular 

 cows, for the germ that affects cattle causes some of the tuber- 

 culosis in children. Dr. William H. Park, a noted authority on 

 bovine (cow) tuberculosis, states that in a large number of cases 

 investigated by him 57 per cent of abdominal tuberculosis in 

 very A^oung children and 47 per cent of such tuberculosis in 

 children under five years of age was of the bovine type. For- 



1850 1860 1870 1880 1890 1900 1910 1920 1930 



Curve sho"wing a decreasing death rate from 

 tuberculosis ; the number of deaths each year 

 per 100.000. 



