CHAPTER XLIII 



THE MICROBE OF PNEUMONIA 



PNEUMONIA is one of the worst and most dreaded 

 diseases man has to fight. In the United States 

 it destroys no less then 106,000 lives every year. 

 This means, in all countries, not less than 2,120,- 

 000. Infancy, manhood, old age are alike its vic- 

 tims. 



The disease, though always essentially the same, 

 yet comes in different forms. Though in every 

 case caused by a microbe, the microbe varies ac- 

 cording to the form of the disease. Each variety 

 of the disease is caused by a corresponding variety 

 of the microbe. 



One form of the disease is called croupous 

 pneumonia. In the lung it acts somewhat like 

 croup in the throat. First, the lining membranes 

 are inflamed. Second, the lung fills. Third, the 

 lung becomes more or less solid. Fourth, pus 

 forms in the lung. If the disease is not arrested 

 before the fourth, or even the third state, it is al- 

 most sure to prove fatal. 



The microbe which causes this form of the dis- 

 ease is represented in Fig. 76. In shape it is oval, 

 with ends rounded. Sometimes pointed. In its 

 longer diameter it is the one twenty-five thou- 



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