CLASSIFICATION OF PNEUMOCOCCI 115 



Peizer, 274 expanded the classification to include twenty-nine types 

 in addition to the first three original types of Dochez and Gillespie, 

 making a total of thirty-two specific types. To show how the new 

 types compared with atypical strains described by other authors, 

 the following list taken from the paper by Cooper and her associ- 

 ates may be repeated here : 



Type IV — Pneumococcus 10 (Griffith), Group IVB (Robinson) 



Type V — Sub IIA (Avery), Group IVE (Robinson) 



Type VI— Sub IIB (Avery) 



Type VIII — Group IVA (Robinson), atypical III (Sugg, Gaspari, 



Fleming, and Neill) 

 Type XV — Pneumococcus 98 (Griffith) 

 Type XXI — Pneumococcus 160 (Griffith) 

 Type XXII — Pneumococcus 41 (Griffith) 



The majority of the thirty-two types showed only slight cross- 

 reactions; Types II and V; III and VIII; VII and XVIII; and 

 XV and XXX being exceptions. Only a small percentage of strains 

 isolated in New York City could not be serologically identified by 

 Cooper and her co-workers. 



In the study just cited, from the majority of horses immunized 

 for a period of more than a year serums with 500 to 1,000 units 

 were obtained, and by the concentration of serum of lower po- 

 tency, Cooper and her associates obtained preparations equal to or 

 stronger than high-grade unconcentrated serums. In addition, the 

 authors developed potent bivalent serums for those types which 

 gave marked cross-agglutinative reactions. 



The original publication should be consulted for full informa- 

 tion concerning the incidence and severity of cases due to the dif- 

 ferent types, their presence in normal individuals and in spinal 

 meningitis, and their virulence for mice. The original serological 

 classification of Dochez and Gillespie as amplified and extended by 

 the additions discovered by Olmstead and by Cooper and her col- 

 leagues covers practically all strains that have been studied and is 

 now tentatively accepted as standard. 



