412 BACTERIOLOGY. 



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-Avhite, 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 

 diphtheria 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 growing at 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 ba- 

 cillus diphtherice, and is found to belong, not to the 

 crystallizable ptomaines, but to the toxic albumins 

 bodies which, in their chemical composition, are analo- 

 gous to the poison of certain venomous serpents. By 

 the introduction of this toxalbumin, as it is called, into 

 the tissues of guinea-pigs and rabbits the same patho- 

 logical alterations may be produced that we have seen 

 to follow inoculation with the bacilli themselves, except, 

 perhaps, the production of false membranes. 



