xix BACTERIA AND DISEASES 291 



tions from the bowels, which should be carefully disin- 

 fected. When dysentery prevails, all drinking water 

 should be thoroughly boiled, and no uncooked vegetables 

 should be eaten. 



200. Diphtheria. This disease is caused by a rod- 

 shaped bacillus. Diphtheria belongs to the class of in- 

 fectious diseases, but is probably also highly contagious. 

 The germs of diphtheria come from the mouth and 

 throat of the patient. They may be coughed i up in 

 bits of the membrane that forms in the throat, and 

 lodge on the bedclothes, furniture, persons near by, and 

 on the walls of the room. The germs may become 

 completely dry, and still retain life and be able to 

 cause the disease in another person. Diphtheria in 

 the house of the dairyman has been known to infect 

 the milk and cause a 'general outbreak among his 

 patrons. Cattle probably never have 

 the disease, but cats have taken it 

 from children and carried it else- 

 where. 



The germs settle in the throat and 

 soon cause a yellowish white mem- 

 brane to form, which may completely 

 obstruct the air passages. The dis- FlG - 159. -Bacteria of 



diphtheria. 



ease is accompanied by sore throat, 

 a croupy cough, and a choking sensation. Of course 

 not every case of sore throat is diphtheria, but, if at all 

 serious, it should be looked upon with grave suspicion. 

 Diphtheria is one of the diseases that is being success- 

 fully treated to-day by the use of a germicide made from 



