HISTORY OF PNEUMOCOCCUS: 1875-1890 13 



monia might be caused by other organisms ; ideas that we now 

 know are true but which were scouted at the time. A careful read- 

 ing of Friedlander's original communications makes it difficult to 

 escape the conviction that he, in 1881, saw in the secretions and 

 tissues of pneumonia patients the organism we know as Pneumo- 

 coccus and, in the next two years, accomplished its isolation and 

 cultivation. It seems likely, however, that Friedlander isolated at 

 the same time the bacillus which later came to bear his name. 



One seems justified in assuming as a cause of the divergent opin- 

 ions which have so long persisted in the literature, the statement in 

 Friedlander's communication of 1886 492 that the micrococcus so 

 thoroughly studied by Fraenkel was the coccus he had originally 

 described, but that the organism upon which he was then reporting 

 was neither a coccus nor a bacillus* but a bacterium which he 

 called Kapselbacterium. In addition to short elements, it existed 

 in rod-like and thread-like forms and, furthermore, it was found 

 only in a minority of the pneumonia cases studied — both charac- 

 ters of the Friedlander bacillus. Therefore, in view of all the evi- 

 dence, and with due deference to the opinion of distinguished au- 

 thorities, it would seem that the credit for first indicating that a 

 diplococcus — Diplococcus pneumoniae — might be the cause of 

 pneumonia should be given to Friedlander. To him, also, should go 

 the honor of discovering another etiological agent of pneumonia, 

 Bacillus friedlanderi. 



Afanassiew, 4 in 1884, added suggestive, if somewhat doubtful, 

 information to the question. He, too, obtained ovoid cocci from six 

 cases of pneumonia, but the cultures were not pure and this fact 

 led to uncertainty. Klein, 719 on the contrary, apparently succeeded 

 not only in growing pure cultures of Pneumococcus and in infect- 

 ing mice and rabbits with them, but in recovering the organisms 

 from the test animals and in transmitting the infection in series to 



* It should be borne in mind that, at the time, the criterion for judging 

 whether an organism was a bacillus or a bacterium was the presence of mo- 

 tility in the former and its absence in the latter. 



