CLASSIFICATION OF PNEUMOCOCCI 107 



Lister (1913), 815 studying pneumococci recovered from native 

 laborers in South Africa, was struck by the comparative rarity 

 with which recently isolated pneumococci were opsonized even by 

 serum of pneumonia patients. He succeeded however in obtaining 

 opsonic preparations which showed massive agglutination and 

 marked phagocytosis. Tests on his first four cases suggested the 

 "existence of groups of pneumococci, having distinct serological 

 reactions," and the "presence of specific agglutinins in 'critical' 

 sera from pneumonic patients." Serum from a Group I case failed 

 to react with cultures of Group II, III, or IV pneumococci, and 

 serum for Groups II, III, and IV failed to react with a Group I 

 culture, but any of the Group II, III, and IV serums reacted typi- 

 cally with any of the cultures of Groups II, III, and IV. The nu- 

 merals are Lister's and bear no relation to the designations used 

 by Dochez and Gillespie. It was not until the completion of his 

 work that Lister learnt of the earlier classification. He immedi- 

 ately compared his groups with those of the American authors, 

 and divided his twenty cultures into five groups, A, B, C, D, and E, 

 of which Group A could not be identified with any of the American 

 types, while Group C corresponded to Type I, and Group B to 

 Type II. Lister's E group was later found to be the same as Type 

 III. 



A year later, Lister 816 was able to clarify the apparent confu- 

 sion existing between his classification and that of Dochez and 

 Gillespie. He sent to the American workers dried spleens of mice 

 infected with cultures representing his groups and received from 

 them in return samples of Type I, II, and III serums. This mutual 

 investigation showed that Lister's C and B groups corresponded 

 respectively with the American Types I and II. Since Lister had 

 no E cultures at the time, he could not correlate it with any of the 

 American groups. At the Hospital of the Rockefeller Institute, 

 however, the identification of the E strain as Pneumococcus III 

 was made. In regard to Dochez and Gillespie's Group IV, Lister 

 stated that it was at this point that his classification departed 



