322 BIOLOGY OF PNEUMOCOCCUS 



SUMMARY 



The discovery of bacteria endowed with enzymes capable of 

 breaking down the complex polysaccharides of Pneumococcus is of 

 more than academic interest. Here is a biological agent that in no 

 way interferes with the vital activities of the pneumococcal cell; 

 the cell grows, multiplies, and continues to synthesize the complex 

 capsular carbohydrate peculiar to its serological type, but as soon 

 as the carbohydrate is formed it is stripped from the coccus by the 

 digestive action of the alien bacterial enzyme. The ability of a mere 

 saprophyte to rob a pathogen of its protective covering, and 

 thereby to deprive it of its infective power, is one of the strangely 

 fascinating surprises of bacteriological research, but it has a much' 

 deeper meaning. The nature of this enzymatic action is in accord 

 with the specific chemical constitution and serological behavior of 

 the specific capsular polysaccharide of the pneumococcal type af- 

 fected. By denuding the cell of its capsule through the dissolution 

 of its polysaccharide, the enzyme exposes the cell to the destruc- 

 tive action of the white corpuscles of the blood, and if the tissue 

 cells are functionally vigorous enough, the attack of the invading 

 pneumococci is repelled and the infection aborted. 



The enzymes of certain of these bacterial forms have been shown 

 to save mice, rabbits, and monkeys from all but a massive infection 

 from Pneumococcus and, what is more striking, the enzyme of one 

 bacterial species directs its attack against the members of Type 

 III, for which, as yet, no biological curative agent has been de- 

 vised. The possibilities presented by these recent disclosures en- 

 gage the imagination. The bacteriologist will want to search for 

 still other microbic cells with enzymes capable of consuming the 

 carbohydrates of pneumococci of the other serological types ; the 

 biochemist will desire to know more of the nature of the enzymatic 

 principle existing in these bacterial cells ; while the investigator in 

 immunology will follow this inviting lead toward a resolution of 

 some of the processes operating in infection and resistance. 



