ANTIBODIES TO PNEUMOCOCCUS 361 



three-fourths of the cases of lobar pneumonia tested, and sub- 

 stantiated Blake's observation that pneumonia patients who failed 

 to develop demonstrable agglutinins succumbed to the infection. 



The agglutination curve of the blood of pneumonia patients re- 

 ceiving antipneumococcic serum was employed by Cole (1917) 258 

 to explain variations in the curative action of the serum. 



AGGLUTINATION AND SEROLOGICAL CLASSIFICATION 



In studies carried on by Neufeld and Haendel 991 during the 

 years 1909 to 1912, it was learnt that agglutination of typical 

 and atypical pneumococci corresponded to susceptibility to the 

 protective action of specific immune serum. In 1913, Dochez and 

 Gillespie, 322 by the methods of mouse protection and agglutina- 

 tion, were able to separate strains of pneumococci isolated from 

 cases of lobar pneumonia into four groups. The close agreement in 

 the results demonstrated the value of the agglutination reaction 

 in differentiating pneumococci, while the absence of cross-agglu- 

 tination between the majority of representatives of the fourth 

 group attested the heterogenicity of that class. Hanes 588 applied 

 the method to cultures of Pneumococcus obtained from lobar pneu- 

 monia patients and, while confirming the work of Dochez and Gil- 

 lespie, encountered difficulties in the serological identification of 

 Type III organisms. In attempts to demonstrate specific agglu- 

 tinins in the serum of rabbits highly immunized to cultures of the 

 mucoid variety of Pneumococcus, the results were uniformly nega- 

 tive, but when the decapsulating method of Porges was used, in 

 every instance the organisms agglutinated with homologous Type 

 III serum, showed constant cross-agglutination within the group, 

 and failed to react with immune serum for Types I and II and 

 for streptococci. Hanes, therefore, suggested that henceforth the 

 name Pneumococcus mucosus should be adopted for organisms of 

 this group instead of the older designation, Streptococcus mu- 

 cosus. With the aid of the Porges technique, Nicolle, Jouan, and 

 Debains 1011 obtained agglutination with strains of Pneumococcus 



