252 BIOLOGY OF PNEUMOCOCCUS 



addition, these antiprotein serums did not agglutinate type-specific 

 strains of Pneumococcus or react with the type-specific carbo- 

 hydrate derived from them. This fact points to the capsular poly- 

 saccharide of the cell as the bearer of the type-specific determinant. 

 As a complement to these observations, Avery and Neill 59 added 

 that intact pneumococci, possessing specific antigenic powers un- 

 impaired by cultural or other procedures, gave rise to agglutinins 

 for the homologous type and to precipitins for the type-specific 

 carbohydrate derived from them. When, however, the cell was dis- 

 rupted, the soluble cell-free constituents in the absence of formed 

 elements failed to stimulate the formation of type-specific anti- 

 bodies, but did induce the formation of antibodies reactive with 

 pneumococcal protein regardless of the type from which the lat- 

 ter was derived. The data pointed to the dissociation of the carbo- 

 hydrate and protein fractions during the process of cell dissolution 

 with the subsequent change in the type-specific action of the con- 

 stituents, or, put in another way, to the loss of antigenic function 

 of the polysaccharide portion of the cell when freed from its con- 

 jugated protein. 



ISOLATION OF CARBOHYDRATE FRACTIONS 



From the results reported by Schiemann and Caspar, 1228 it 

 would appear that they had isolated two carbohydrate fractions 

 from Type II Pneumococcus. One of the protein-free substances 

 was soluble in alcohol, gave specific precipitation with homologous 

 serum, and was antigenic in that it immunized mice. The second 

 fraction also gave specific precipitation but was insoluble in alco- 

 hol. The preparations were made by boiling sodium taurocholate 

 solutions of pneumococci with acetic acid. Both substances and the 

 one obtained from a Type III strain were evidently free from pro- 

 tein, since the authors could detect no nitrogen in the prepara- 

 tions, and yet contrary to the results of Perlzweig and Steffen and 

 of Avery and Morgan, the non-nitrogenous fractions possessed an- 

 tigenic power since they produced immunity in mice. Schiemann 



