PROBLEM 2. How We Call Conquer Some Diseases 



321 



Year 



Rate per 

 100,000 

 Population 

 250 



200 



150 



100 



Adapted from G. J. Drolet, Statistician 

 New York Tuberculosis and Health Association, Inc. 



Fig. 292 A graph showing the tuberculosis death rates in New York City and in the 

 United States as a whole fro?n 1900 to 1944. Compare the death rates in 1900 and 1944. 

 What has been done to cause the change in rate of death from tuberculosis? Now com- 

 pare the death rate in New York City with the rate in the country as a whole. What 

 might be the explanation of this difference in rates? 



energies to finding a germ that might 

 cause anthrax. Anthrax, a common dis- 

 ease of sheep and cattle, was responsible 

 for a great loss of money. It was known 

 to affect man also. Another bacteriolo- 

 gist had declared that a specific germ 

 caused the disease, but he had not pro- 

 duced convincincr evidence. To check 

 this belief, Koch and others working in 

 bacteriological laboratories in various 

 countries spent years in patient investi- 

 gation and experimentation. Koch finally 

 succeeded in finding the bacillus and 

 proving that it and it alone caused an- 

 thrax. Gradually enough evidence was 

 collected to convince those who studied 

 disease that each of the common infec- 

 tious diseases is caused by some definite 

 organism. Thus the germ theory of dis- 

 ease was established. 



Another important discovery. Some 

 years after his discovery of the anthrax 



germ Koch found the cause of tubercu- 

 losis. His seemingly unimportant work 

 on staining brought him success. He was 

 able to develop a special method which 

 stained one species of bacterium only. 

 Other species of the same shape and gen- 

 eral appearance did not take the stain. 

 The one which took the stain appeared 

 regularly on his slides when he examined 

 the tissues of animals that had died 

 of tuberculosis. His newly-developed 

 method of distinguishing species of bac- 

 teria by staining enabled him to single out 

 the germ which caused tuberculosis. 



Tuberculosis was well named the 

 "great white plague," for this disease 

 took an enormous toll of lives. It prob- 

 ably reached its peak when the indus- 

 trial revolution brought the growth of 

 towns and small cities, and when people 

 becran to work long hours in crowded 

 factories. In 1780 in England, iioo out 



