3o8 MICRO-ORGANISMS AND DISEASE [chap. 



bacillus definite pathological results — inflammation, with 

 something like diphtheritic necrotic membrane — can be 

 obtained by rubbing them into an abraded surface of the- 

 mucous membrane (mouth, trachea) of rabbits, fowls, or 

 pigeons, and Roux and Yersin found the same ; but such 

 results are not easily and constantly obtainable either with 

 human diphtheritic membranes or with the cultures of the 

 diphtheria bacillus. By subcutaneous inoculation of 

 guinea-pigs with diphtheritic membrane, and particularly 

 with cultures of the bacillus diphtheria, definite results are 

 obtained. After subcutaneous inoculation with cultures a 

 few days old the result is very rapid and more striking than 

 with diphtheritic membrane ; for obtaining very acute 

 results only a small particle, not more than what can be 

 removed from a colony with the end of a platinum loop, 

 often suffices. In the severe cases produced by injecting 

 several minims of a recent broth culture (forty-eight hours 

 old) the animals are very quiet already after twelve or 

 sixteen hours ; a soft, painful swelling is found at the seat 

 of inoculation. During the second day the hair is erect, the 

 eyes are small, the temperature is raised ; the animals are 

 tremulous and refuse food ; the condition grows rapidly 

 worse, movement ceases, the body temperature rapidly falls, 

 and they are found dead before thirty to forty hours are 

 over. In other cases the illness lasts two to three days ; in 

 still others as long as five days, or even more. The 

 younger the culture the more active it is, and the more 

 bacilli are injected the shorter the illness. On post-mortem 

 examination we find haemorrhage and oedema in and about 

 the place of inoculation, in the subcutaneous and muscular 

 tissue, extending sometimes over considerable areas ; when 

 inoculation is made into the groin the changes (haemorrhage 

 and cedema) extend over the thigh, abdomen, and even 



