HISTORY OF PNEUMOCOCCUS: 1890-1900 25 



Discovered by the present writer in the blood of rabbits inoculated 

 subcutaneously with his own saliva in September, 1880; by Pasteur in 

 the blood of rabbits inoculated with the saliva of a child which died of 

 hydrophobia in one of the hospitals of Paris in December, 1880; identi- 

 fied with the micrococcus in the rusty sputum of pneumonia, by com- 

 parative inoculation and culture experiments, by the writer in 1885. 

 Proved to be the cause of croupous pneumonia in man by the researches 

 of Talamon, Salvioli, Sternberg, Fraenkel, Weichselbaum, Netter, 

 Gamaleia, and others. 



Mosny (1892), 932 unconcerned about priority, turned his atten- 

 tion to immunological experiments. He grew virulent pneumococci 

 in broth, heated the cultures at 60°, and then filtered them. The 

 subcutaneous or intravenous injection of the filtrates into rabbits 

 brought about immunity four days later, but the immunity was of 

 a low order. The serum of the rabbits so treated gave protection 

 only when injected before or at the same time with the inoculated 

 culture. Mosny could detect no bactericidal action of the immune 

 serum. The cocci, on the contrary, grew fully as well in immune as 

 in normal serum. In watching the growths he noted a change in the 

 physical appearance of the immune serum-culture mixture which 

 we now know must have been agglutination. Mosny, like Klebs, and 

 more particularly Metchnikoff, saw something new and told of it, 

 unconscious that he had made a discovery. 



The toxin idea was then current, and Issaeff, 673 using sterilized 

 broth cultures of virulent pneumococci and chloroform and glyc- 

 erol extracts of infected blood, interpreted the effects following 

 their intravenous injection as being due to a toxin, but frankly 

 confessed that the immune serum so obtained had no antitoxic 

 properties ; neither did it show any bactericidal action. The serum 

 did, however, promote phagocytosis, and Issaeff quite rightly con- 

 cluded that phagocytosis played a most important part in im- 

 munity to Pneumococcus. Emmerich 856 also entertained the toxin 

 idea, but instead of heating or filtering broth cultures, injected 

 them in diluted state. He stressed the desirability of using virulent 

 strains, as well as the necessity of taking blood only from highly 



