290 BACTERIOLOGY. 



originated. These particles always stain much more 

 intensely than do the normal nuclei of the part. ' 



These peculiar alterations, as Oertel has shown, in 

 their distribution, are characteristic of human diphtheria, 

 and the demonstration of similar changes in animals 

 inoculated 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, necrotic, distinctly diphtheritic layer. 

 Around the wound the subcutaneous tissues will be 

 oedematous. The lymphatic glands at the angle of the 

 jaws will be swollen and reddened. The mucous mem- 

 brane 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 observed 

 in the same situation in cases of human diphtheria. 

 In the pseudo-membrane and in the oedematous 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 pointof inoculation, their absence from the internal 

 organs, and the changes brought about in the cellular 

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



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

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

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

 1892. 



