116 UNIVERSITY OF WISCONSIN STUDIES 



here in the United States. No one, so far as I know, has at- 

 tempted to differentiate them on clinical grounds. 



Therapeutically they responded promptly to potassium 

 iodide as did the later French and American cases. 



The morbid anatomy and histology in the human were, so 

 far as studied, the same in the two types, the lesions being 

 those of a chronic abscess. In experimental animals the 

 lesions produced by the two types are identical as admitted by 

 Gougerot. 



Bacteriologically there is greater opportunity to detect 

 minute or subtle differences should they be present and these 

 we shall consider in detail. In the cases of Schenck and of 

 Hektoen and Perkins, the organisms were not seen in the 

 human tissues or in the pus. In experimental animals the 

 organisms appeared as oval and elongated forms with occa- 

 sional round forms. They stained with Gram. In no way 

 did they differ from the forms seen in tissues infected with 

 organisms of the French strains. I have made a special 

 study 20 of the tissue forms in experimental animals using 

 strains from France and from America as well as the Schenck- 

 Hektoen strain. No differences could be detected between 

 them. When these various strains are grown in animal fluids, 

 blood etc., in the test tube, elongated forms similar to those 

 seen in the tissues are produced and here again no differences 

 between the various strains were noted. 



The question of the virulence of the various strains may 

 not be of any importance in differentiation since this property 

 is such a variable one. However, it may be stated that the 

 Schenck-Hcktoeii strain even after years of artificial culture 

 is still about as virulent for rats as are the freshly isolated 

 strains of the French type. According to the paper of 

 Schenck, these organisms were virulent for mice and dogs. 

 Hektoen and Perkins produced lesions in mice, dogs, rats and 

 guinea pigs (slight). As far as these results are comparable 

 with those obtained with the French and later American 

 strains, they agree in all essential points. 



We now come to a discussion of the morphological and 

 cultural characteristics, both microscopic and macroscopic, of 



'- Davis, Jour. Infect. Diseases, 12, p. 453, 1913. 



