PATHOGENIC PROPERTIES. 307 



particles always stain much more intensely than do the 

 normal nuclei of the part. 1 



These peculiar alterations, as Oertel has shown, in their 

 distribution, are characteristic of human diphtheria, and 

 the demonstration of similar changes in animals inocu- 

 lated with this organism is important additional proof 

 that diphtheria is caused by it. 



An affection may be produced by the inoculation of 

 certain animals that is in all respects identical with the 

 disease diphtheria as it exists in man. If one opens the 

 trachea of a kitten and rubs upon the mucous membrane 

 a small portion of a pure culture of this organism, the 

 death of the animal usually ensues in from two to four 

 days. At autopsy the wound will be found covered with 

 a grayish, adherent, uecrotic, distinctly diphtheritic 

 layer. Around the wound the subcutaneous tissues 

 will be cedematous. 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 

 bacilli were deposited will be covered with a tolerably 

 firm, grayish-white, loosely attached pseudo-membrane 

 in all respects identical with the croupous membrane ob- 

 served in the same situation in cases of human diph- 

 theria. In the pseudo-membrane and in the redematous 

 fluid about the skin-wound, bacilli diphtherice 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 



1 See "The Histological Changes in Experimental Diphtheria," also " The 

 Histological Lesions produced by the Toxalburain of Diphtheria," by Welch 

 and Flexner. The Johns Hopkins Hospital Bulletin, August, 1891, and March, 



