364 DIPHTHERIA. 



made from the blood and internal organs giving negative 

 results. If a non-fatal dose of a culture be injected, a local 

 necrosis of the skin and subcutaneous tissue may follow at 

 the site of inoculation. 



In rabbits, after subcutaneous inoculation, results of the 

 same nature follow, but these animals are less susceptible 

 than guinea-pigs, and the dose requires to be proportion- 

 ately larger. The dog and sheep are also susceptible to 

 inoculation with virulent bacilli, but the mouse and rat 

 enjoy a high degree of immunity. 



Klein found that cats also were susceptible to inoculation. The 

 animals usually die after a few days, and post mortem there is well- 

 marked nephritis. He also found that after subcutaneous injection in 

 cows, a vesicular eruption appeared on the teats of the udder, the fluid 

 in which contained diphtheria bacilli. The animals gradually wasted 

 and died after two or three weeks, the changes in the internal viscera 

 being of the same nature as those in other animals. At the time of 

 death the diphtheria bacilli were still alive and virulent at the site of 

 injection. The striking fact in connection with these experiments is 

 that the diphtheria bacilli passed into the circulation and were present 

 in the eruption on the udder. He considers that this may throw light 

 on certain epidemics of diphtheria in which the contagion was apparently 

 carried by the milk. Further light is required on this subject. 



Intraperitoneal injection of the bacilli in sufficient 

 quantity in the guinea-pig produces death less rapidly than 

 when the same dose is injected subcutaneously. The 

 bacilli are chiefly confined to the peritoneum and gradually 

 diminish in number. 



Intravenous injection of virulent cultures in the rabbit 

 often produces death within three days, there being symp- 

 toms of general poisoning with great prostration and 

 muscular feebleness ; there may also be well-marked 

 nephritis. In such experiments Roux and Yersin found 

 that the bacilli rapidly disappeared from the blood, and 

 even after the injection of i c.c. of a broth culture no trace 

 of the organisms could be detected by culture after twenty- 

 four hours. 



The Toxines of Diphtheria. As in the above experiments 

 the symptoms of poisoning and ultimately a fatal result occur 



