142 BIOLOGY OF PNEUMOCOCCUS 



in bile, and had largely lost their type-specificity. Single-cell cul- 

 tures propagated from S colonies, after repeated transplants 

 under unsuitable conditions, produced some R variants, while sin- 

 gle-cell cultures from R colonies, under the same circumstances, re- 

 mained constant in character. 



SPECIES-SPECIFICITY OF ROUGH FORMS 



A few months later, Reimann 1126 published these further conclu- 

 sions: 



Immune sera prepared with the degraded or variant forms of pneu- 

 mococci (R strains) are similar in their reaction to sera prepared with 

 the protein or cell solutions of pneumococci. They contain antibodies re- 

 active with the protein of all types of pneumococci, but no antibodies 

 reactive with the type-specific substances. Pneumococci of the variant 

 or R form, regardless of type derivation, are serologically identical and 

 have the antigenic characteristics of pneumococcus protein. They evoke 

 the species-specific and not the type-specific antibodies. Antipneumo- 

 coccic sera produced by immunization with S strains may contain spe- 

 cies-specific antibodies in addition to those which are type-specific. 

 Each kind of antibody can be removed separately from these sera by 

 selective absorption with the R and S strains of pneumococci. 



These fundamental observations were later to be confirmed and ex- 

 plained by the discoveries of Avery and Heidelberger of the anti- 

 genic chemical constituents of the pneumococcal cell. 



Takami, 1373 contemporaneously with Amoss and Reimann, added 

 a few new facts about variation. His study included certain strains 

 that were apparently stable in their original characters, since they 

 gave rise to no variants even after two or three years' cultivation. 

 There were other strains that showed a strong tendency to vary, 

 and in a short time became so changed that they no longer pro- 

 duced any typical colonies. In agglutinative abilities the same rule 

 held true. There appeared to be no direct relation between de- 

 crease of agglutinability and atypical colony formation. The only 

 two characters that were closely connected were bile-solubility and 



