CHAPTEK XXIII. 



DIPHTHERIA. 



Diphtheria is a specific infectious disease, especially of children, 

 characterised most commonly by inflammation, and infiltration with 

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

 pharynx, larynx and trachea, followed by necrosis of the mucous 

 membrane and the formation of a greyish-white false membrane, 

 the diphtheritic membrane. In some cases a diphtheritic membrane 

 forms in the stomach, intestine, the urinary 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 baciUi. 

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

 internal 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 to be due to a living contagium, 

 these insanitary conditions would afford a suitable environment 

 predisposing to the development, and facilitating 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 possibility 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 

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

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



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