298 BIOLOGY OF PNEUMOCOCCUS 



A careful examination of the specifications which have been 

 given in all these reports would enable one to make a tentative and 

 partial chemical reconstruction of the pneumococcal cell. The 

 basic protoplasm would contain protein — a nucleoprotein — with a 

 more or less constant composition for all pneumococci regardless 

 of serological type. This common component would, in some re- 

 spects, bear a close resemblance to the protein of other members 

 of the genus, Streptococcaceae, and a more general resemblance to 

 that of other more distantly related microorganisms. Another con- 

 stituent of the protoplasm would be lipids, probably combined with 

 the protein and conceivably loosely linked to the carbohydrate. 

 Then the substance of the cell would also include a polysaccharide 

 — a carbohydrate of the nature of the C Fraction of Tillett and 

 Francis. This phosphorus and nitrogen containing carbohydrate 

 would, like the nucleoprotein, be possessed by every Pneumococcus, 

 whether of full virulence or degraded below the stage of any type 

 identity. There would naturally be inorganic salts, but since little 

 is known about them, their actual composition cannot be defined. 

 In this viable, watery solution of colloids and crystalloids there 

 would be enzymes — proteases, lipases, invertases, and saccharases 

 — active in the metabolic processes of the cell and potentially able 

 to destroy it. 



This globular mass of protoplasm would be surrounded by a 

 shielding envelope or capsule, largely carbohydrate in nature. The 

 capsular material would be present when the cell was living in a fa- 

 vorable environment, in greatest amount when the surroundings 

 were ideal, but entirely lacking when the cell had suffered from se- 

 vere degenerative processes. But with or without it, these particu- 

 lar bacterial cells would still be pneumococci, their identity as such 

 resting upon their somatic nucleoprotein and carbohydrate. 



The normal Pneumococcus, however, would possess in its capsule 

 a polysaccharide that would serve to distinguish the organism 

 from many of the other members of the species. These complex car- 

 bohydrates would differ in their content of nitrogen, of phos- 



