II. A SEARCH INTO THE NITRATE AND NITRITE 

 COiNTENT OF WITTE'S 'PEPTONE." 



WITH SPECIAL REFKRKXCE TO ITS INFLUENCE ON THE DEMONSTRATION OF 

 THE INDOL AND CHOLERA-RED REACTIONS. 



By W.^r. B. Wherry, M. D., BiKii'rio/oi/i.st, Hiolot/iral Tjthorafoni. 



Ill a previons ])ul)lication from the laboratoiy' I concluded, by 

 ratlier rough I'xperiniental methods and deductions, that the 

 cliolera spirillum is not a nitrifying organism and that the 

 successful demonstration of the cholera-red reaction in a culture 

 grown in a solution of Witte's "peptone" depends upon the 

 reduction of a trace of nitrates. I was unaware at tlie time my 

 experiments were performed that Petri'- and Bleisch'' had already 

 performed quite extensive and conclusive experiments upon this 

 point. The latter worker also pointed out that the presence of an 

 excess of nitrates or nitrites in tlie medium interfered with the 

 reaction and that the nitrate content of ordinary bouillon is so 

 inconstant as to make it valueless for diagnostic purposes. 



Some peculiar results in testing for indol, during the study of 

 some Ijacteria from a case of irregular fever, emphasized for me 

 the urgent necessity of adopting methods of preparing and testing 

 media whicli would indicate the presence or absence of certain 

 ciiemical ((iiistituents influencing such a })iochemical test. This 

 led to an investigation into the manner in which nitrates and 

 nitrites may gain an entrance to niedia, and on the influence of 

 such variations on tlie demonstration of indol and cholera-red 

 reactions. 



^ Biilliini No. 1!) [lUO-i), Bioloijiciil Lal)f)rat()ry, Bureau of Government 

 Laboratories, Manila, P. I. 

 ''('. Ji. hs'89, 5, 5(51. 

 ^Zuit./iir Hi/;;, ii. lufvU., JSn.'i, 14, 103. 



81 585 2 17 



