400 BACTEMIOLOOT. 



to four days. At autopsy the wound will be found 

 covered with a grayish, adherent, necrotic, distinctly 

 diphtheritic layer. Around the wound the subcuta- 

 neous tissues will be oedematous. The lymphatic glands 

 at the angle of the jaws will be swollen and reddened. 

 The mucous membrane of the trachea at the point upon 

 which the bacteria were deposited will be covered with 

 a tolerably firm, 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 O3dematous fluid about the skin-wound bacillus 

 diptheria3 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 internal organs, and the changes brought about in 

 the cellular elements of the internal organs there is 

 but one interpretation for this process, viz., that it is 

 due to the production of a soluble poison by the bac- 

 teria confined to the site of inoculation, which, gaining 

 access to the circulation, produces the changes that we 

 observe in the tissues of the internal viscera. 



This poison has been isolated from cultures of bacillus 

 diphtheria?, and is found to belong, not to the crystal- 

 lizable ptomaines, but to the toxins bodies which, in 

 their chemical composition, are analogous to the poison 

 of certain venomous serpents. By the introduction of 

 this toxin into the tissues of guinea-pigs and rabbits the 

 same pathological alterations may be produced that we 

 have seen to follow inoculation with the bacilli them- 

 selves, except, perhaps, the production of false mem- 

 branes. 



