CHAPTER XXIII. 



DIPHTHERIA. 



Diphtheria is a specific infectious disease, especially of children, 

 characterised most commonly by inflammation, and infiltration vrith 

 Ivmph cells and fibrine, of the mucous membrane of the fauces, 

 pharvnx, larvnx and trachea, followed by necrosis of the mucous 

 membrane and the formation of a greyish-"5rliit« false membrane, 

 the diphtheritic membrane. In some cases a diphtheritic membrane 

 forms in the stomach, intestine, the ui-inary organs and in wounds. 

 After the separation of the membrane an ulcer remains, which may 

 gradually heal. In the superficial part of the diphtheritic membrane 

 there are masses of bacteria including cocci, streptococci, and bacilli. 

 The diphtheria bacilli are not found in the blood or in the 

 int-ernal organs. There is no doubt of the fact that diphtheria 

 is a disease which can be communicated from one person to 

 another ; but the question of its origin is still a vexed one. There 

 is a close association with insanitary conditions and decaying 

 animal and vegetable refuse, and dampness. Localities with damp 

 houses, defective drainage, and a cold exposure, are favourable 

 to the development of diphtheria; but that does not necessarily 

 indicate that these conditions can originate it. On the other 

 hand, assuming the disease t-o be due to a living contagium, 

 these insanitary conditions would afford a suitable environment 

 predisposing to the development, and faeihtating the spread, of the 

 disease. Scarlet fever and measles predispose to diphtheria ; and 

 defective sanitary conditions, causing sore throat, may indirectly 

 act as a predisposing cause. A great many cases have been quoted 

 to illustrate the possibUity of the conveyance of diphtheria by milk, 

 and the theory which best harmonises with all these observations is 

 the existence of a specific bacillus, which may be readily transferred 

 from the throat of the diseased to the healthy ; which finds also in 

 millr a suitable soil for its growth, and by its agency may be trans- 

 mitted to the consumer. Such a bacillus was discovered by LbfiSer, 



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