INOCULATION EXPERIMENTS. 363 



Effects of Inoculation. In considering the effects pro- 

 duced in animals by experimental inoculations of pure 

 cultures, we have to keep in view the local changes 

 which occur in diphtheria, and also the symptoms of general 

 poisoning. 



Loffler in his original paper stated that in the case of 

 rabbits, guinea-pigs, pigeons, and fowls the bacilli taken 

 from pure cultures produced no change on healthy mucous 

 membranes, but when the latter were injured by scarification 

 or otherwise the production of false membrane resulted. A 

 similar result was obtained when the trachea was inoculated 

 after tracheotomy had been performed. In this case the 

 surrounding tissues became the seat of a blood stained 

 oedema, and the lymphatic glands were enlarged, the general 

 picture resembling pretty closely that of laryngeal diphtheria. 

 These results have been amply confirmed by other ob- 

 servers. The membrane produced by such experiments is 

 usually less firm than in human diphtheria, and the bacilli 

 are not generally found in such large numbers in the mem- 

 brane. Rabbits inoculated after tracheotomy often die, and 

 Roux and Yersin were the first to observe that in some 

 cases paralysis may appear before death. 



Subcutaneous injection in guinea-pigs, of diphtheria bacilli 

 in a suitable dose, produces death within thirty-six hours. 

 On section at the site of inoculation there is seen a small 

 patch of greyish membrane, whilst in the tissues around 

 there is extensive inflammatory oedema, often associated with 

 haemorrhages, and there is also some swelling of the corre- 

 sponding lymphatic glands. The internal organs show 

 general congestion, the suprarenal capsules being especially 

 affected and .often showing haemorrhage. The renal epithe- 

 lium may show cloudy swelling, and there is often effusion 

 into the pleural cavities. After injection the bacilli increase 

 in number for a few hours, but multiplication soon ceases, 

 and at the time of death they may be less numerous than 

 when injected. The bacilli remain quite local, 1 cultures 



1 This may be stated as a general law, though in exceptional cases a 

 few bacilli have been detected in internal organs. 



