340 DIPHTHERIA. 



made from the blood and internal organs giving nega- 

 tive 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 changes resulting 

 being of a somewhat similar nature to those described. 

 The animals usually die after a few days, and post mortem 

 there is well-marked nephritis. He also found that after sub- 

 cutaneous 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 to 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 con- 

 nection 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. 



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 

 symptoms of general poisoning with great prostration, and 

 muscular feebleness. There may also be well-marked 

 nephritis, but 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 



