492 APPLICATION OF METHODS OF BACTERIOLOGY 



regular in outline, while others are irregularly crescentic, 

 dumb-bell, flask-shape, whetstone-shape, or bladder-like 

 in form. Occasionally nuclei having the appearance of 

 being pinched or drawn out can be seen. At some points 

 the fragments are grouped in isolated masses, indicating the 

 location of the nucleus from the destruction of which they 

 originated. 'These particles always stain much more in- 

 tensely than do the normal nuclei of the part. 1 Oertel 

 showed long before bacillus diphtherise was discovered that 

 these peculiar alterations in cell nuclei, both in distribution 

 and appearance, 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. 



By the inoculation of certain animals an affection may 

 be produced in all respects identical with diphtheria as it 

 exists in man. If one open the trachea of a kitten and rub 

 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 diph- 

 theritic layer. Around the wound the subcutaneous tissues 

 will be edematous. 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 bac- 

 teria were deposited will be covered with a tolerably firm, 

 grayish-white, loosely attached pseudomembrane in all 

 respects identical with the croupous membrane observed 

 in the same situation in cases of human diphtheria. In the 



1 See The Histological Changes in Experimental Diphtheria, also Th.e 

 Histological Lesions Produced by the Toxalbumin of Diphtheria, by Welch 

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

 1892. 



