COMMUNICABLE DISEASES 385 



cancer, without seriously injuring normal tissues. In skin cancer the 

 properly adjusted dosage and time exposure of the radium emanations 

 has resulted in the complete killing of the cancerous epithelium, so that 

 it could be lifted off, showing the normal granulation tissue underneath. 

 Many volumes have been written about cancer and many scientific 

 bodies have given much time and attention to the cancer problem, which 

 is a very serious one, but the solution is not yet found. 



H. Plague. This disease, which is also known as black plague, the 

 pest, bubonic plague, black death, etc., is essentially a filth disease. The 

 primary cause is the non-sporogenous Bacillus pestis. The plague has 





FIG. 94. PIG. 95. 



PIG. 94. Bacillus pestis. Does not form spores and is very easily killed. The ends 

 stain more heavily than the middle. Involution forms may occur. Sometimes the 

 cells become encapsuled as shown in the figure. 



FIG. 95. Bacillus cholera also known as Spirillum cholera, the case of Asiatic 

 cholera. 



occurred epidemically from time to time throughout all ages. It is most 

 virulent and most prevalent (endemic) in the crowded cities of the warmer 

 countries (Oriental cities), where the sanitary conditions are often very 

 bad. The disease is highly contagious and infectious and is communicable 

 not only to man but also to rats, mice, dogs, squirrels and cattle. Rats, 

 and the fleas upon -them, are the principal carriers of the disease, although 

 other animals, as ants and flies, may also act as carriers. 



There are several forms of the plague of which the pneumonic is the 

 most dangerous and most infectious because the bacilli are spread by 

 coughing and sneezing. 



In this disease thorough disinfection is of the greatest importance. 

 The entire body of the patient should be washed with a disinfecting solu- 

 tion (1-1200 bichloride of mercury). Disinfect everything used about the 

 patient. After death or recovery everything used by the patient should 

 be destroyed by burning. 

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