(From the Memorial Institute for Infectious Diseases, Chicago.) 



THE MECHANISM OF NATURAL 

 AND ACQUIRED STREPTOCOCCUS IMMUNITY. 



EY 



GUSTAV F. RUEDIGFR. 



PROFESSOR OF BACTERIOLOGY AND PATHOLOGY, UNIVERSITY OF NORTH 

 DAKOTA, GRAND FORKS, N. D. 



INTRODUCTION. 



A great deal of work has been done on the mechanism of strepto- 

 coccus immunity both with normal and with immunized animals, but 

 many points are still left entirely in the dark. In the experiments de- 

 scribed in this paper, an attempt is made to throw additional light on 

 some of these points, but on account of the many inherent difficulties,, 

 the results which I have achieved by no means exhaust the problem. 



Shortly after the publication of his classical paper on phagocytosis 

 in daphnia, MetchnikofP made a study of phagocytosis of streptococci : 

 in the human body, in cases of erysipelas. He concluded from his ob- 

 servations that streptococci gain entrance through abrasions of the skin,, 

 multiply and set up an inflammation. At the same time there is a gath- 

 ering of microcytes about the streptococci, and these take up the latter 

 and destroy them. Macrocytes are also found in considerable numbers, 

 but they do not take up the streptococci, but have, nevertheless, a phago- 

 cyte action in that they take up and remove dead and disabled micro- 

 cytes. 



In 1895 Denys and Leclef* studied the mechanism of immunity in 

 rabbits which had been repeatedly injected with small but gradually in- 

 creased doses of virulent streptococci. Their conclusions may be briefly 

 stated as follows : Immune rabbit serum is not so good a culture medium 

 for streptococci as normal serum but it does not possess any marked, 

 streptococcidal powers. The cell-free fluid from a leucocytic exudate 



*Virdiow's Archiv. 1887, evil., 209. 

 **La Cellule, 1805, XI, 177. 



183473 



