INOCULATIONS OF B. DIPHTHERIA. 251 



grayish- white, loosely attached pseudo-membrane in all 

 respects identical with the croupous membrane observed 

 in the same situation in cases of human diphtheria. 

 In the pseudo-membrane and in the oedematous fluid 

 about the skin-wound, bacilli diphtherise may be found 

 both in cover-slips and in cultures. 



From what we have seen — the localization of the bacilli 

 at the point of inoculation, their absence from the iuternal 

 organs, and the changes brought about' in the cellular 

 elements of the internal organs — there is but one inter- 

 pretation for this process, and that is the production of 

 a soluble poison by the bacteria growing at the seat of 

 inoculation, which gains access to the circulation and 

 produces the changes that we observe in the tissues of 

 the internal viscera. 



This poison has been isolated from cultures of the 

 bacillus of diphtheria by Brieger and Frankel. It is 

 found to belong, not to the crystallizable ptomaines, but 

 to the toxic albumins. By the introduction of this tox- 

 albumin, as it is called, into the tissues of guinea-pigs 

 and rabbits the same pathological alterations may be 

 produced that we have seen to follow the result of inocu- 

 lation with the bacilli themselves, except, perhaps, the 

 production of false membrane. 



Prepare cover-slip preparations from the mouth cavity 

 of healthy individuals and from those having decayed 

 teeth. Do they correspond in any way with those made 

 from diphtheria ? Do the same with different forms of 

 sore-throat. Do the peculiarities of any of the organ- 

 isms suggest those of the bacillus of diphtheria? Wherein 

 is the difference? 



In cultures and cover-slips made from both diphtheria 



