100 BIOLOGY OF PNEUMOCOCCUS 



coccus still persists. Coca, 246 after continuing the investigation of 

 the toxic principle in Pneumococcus, announced additional data in 

 1936. When the pneumococcal cultures were grown in the presence 

 of oxygen a toxic substance was formed but it was devoid of anti- 

 genic properties. When, however, carbon dioxide was supplied to 

 the growing cultures, the sterile filtrates were not only toxic but 

 antigenic. According to Coca, the pyrogenic toxin seemed to be 

 type-specific and was not the same as the type-specific polysac- 

 charide. Evidence was presented purporting to show that the in- 

 jection of the toxic filtrates into the human body or pneumococcal 

 disease in human subjects provoked neutralizing substances in the 

 serum for filtrates of the homologous type, which the author be- 

 lieved were specific antitoxins. 



A careful reading of original papers dealing with the subject of 

 toxin production by Pneumococcus fails to bring conviction that 

 the substances or extracts described should be looked upon as 

 true soluble toxins. The principle involved in their formation or 

 preparation, that is, disintegration of the pneumococcal cell by 

 self-proteolysis, bile solution, or freezing and thawing; the nature 

 of the local and systemic reactions the materials evoke; the acute 

 anaphylactoid death produced in guinea pigs ; and the feeble anti- 

 genic powers, all argue for the classification of the so-called toxins 

 with the proteins of smaller molecular size formed in the hydrolysis 

 of whole proteins. One has only to recall the work of Vaughan 1447 

 and of others on the effects of the cleavage products of bacterial 

 and of pure proteins, and the many studies on proteoses and pep- 

 tones, to be impressed by the similarity between the alleged pneu- 

 mococcal toxins arising from the autodigestion of the somatic pro- 

 tein of Pneumococcus and protein poisons. The slight antigenic 

 power of the pneumococcal derivatives and their seeming lack of 

 specificity is easily explained when one remembers that the hy- 

 drolysis of proteins is not always an orderly, step-by-step process. 

 Along with the formation of proteoses and peptones, or polypep- 

 tids and amino acids there may be traces of proteins of larger 



