INOCULATION EXPERIMENTS. 339 



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 sur- 

 rounding tissues became the seat of a blood-stained oedema, 

 and the lymphatic glands were enlarged, the general pic- 

 ture 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 

 membrane. Rabbits inoculated after tracheotomy often 

 die, and Roux and Yersin were the first to observe that in 

 some cases paralysis similar to that produced by other 

 methods to be described, may appear before death. 



Subcutaneous injection in guinea-pigs, of diphtheria bacilli 

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

 At the site of inoculation there is 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 corresponding lym- 

 phatic glands. The internal organs show general conges- 

 tion, the suprarenal capsules being especially affected and 

 often showing haemorrhage. The renal epithelium 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 this 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. 



