106 BIOLOGY OF PNEUMOCOCCUS 



found that the results obtained by protection experiments agreed 

 with those of the agglutination reaction. On the basis of these dis- 

 coveries Neufeld and his colleague were the first to recommend that 

 serums should be developed for all types, since it was thought that 

 there were probably many types and that a given serum always 

 exhibited type-specificity. For the serum treatment of pneumonia 

 the authors suggested that the agglutination test be employed to 

 determine the type of the infecting organism before administering 

 the specific serum. 



The next impetus to serological classification of pneumococci 

 came in 1913 from the work of Dochez and Gillespie. 322 These au- 

 thors, by the methods of protection and agglutination, divided the 

 species into four groups. Groups I and II included over 60 per 

 cent of the strains tested, Group III consisted of organisms of the 

 Pneumococcus mucosus type, and Group IV was a heterogeneous 

 collection of strains that fell into none of the first three divisions 

 and that reacted only with strictly homologous, that is, individual, 

 strain-specific serum. When fourteen different cultures were tested 

 against eleven serums for these heterologous strains, no cross-pro- 

 tection was seen, except in one instance.* 



Dochez and Gillespie's Type I Pneumococcus corresponded to 

 the strain originally isolated by Neufeld and Haendel in 1909 and 

 sent by the latter authors to the Rockefeller Institute. The Ameri- 

 can Type II was identical with Neufeld and Haendel's "Franz" 

 culture, which was a representative of the most commonly occur- 

 ring of the atypical strains. Group IV of the American authors 

 Neufeld preferred to call Group X, and this designation is often 

 found in the German literature. 



The typical and atypical strains of Neufeld and Haendel had, 

 therefore, now been sorted into three definite and specific types and 

 a heterogeneous group of wide immunological diversity. 



* Wirth,i524 in a study (1927) of pneumococci from infections of the ears, 

 sinuses, and throat, found strains of the mucosus type which, irrespective of 

 the presence or absence of slimy growth on blood agar, agreed in their aggluti- 

 native characteristics with those of the American Type III. Wirth recom- 

 mended that the name Streptococcus mucosus therefore be abandoned. 



