THE TOXICITY OF VICTORIA BLUE 4 R. FOR B. PARA- 



TYPHOSUS A, B. PARATYPHOSUS B AND 



B. ENTERITIDIS 



OSCAR TEAGUE 



From the Department of Hygiene, Loomis Laboratory, Cornell Medical College, 



New York 



While studying three years ago the relative toxicity of various 

 dyes on strains of B. typhi, B. paratyphi A and B and B. coli, I 

 noticed a marked difference in the toxicity of Victoria blue 4 R. for 

 B. paratyphi A and B. paratyphi B. A careful comparison of the 

 growth of a fairly large number of strains of these organisms 

 and of B. enteritidis, upon the same lot of agar containing dif- 

 ferent amoimts of the stain, was made and, though the results 

 were clearly defined, viz., the paratyphoid B bacillus being 

 more readily inhibited than paratyphoid A and B. enteritidis, 

 yet they did not seem at the time of sufficient importance to 

 warrant their publication. 



At present, however, as infections with these organisms have 

 become more common, and a study of their characteristics has 

 been undertaken in a number of American laboratories, it 

 would seem that my observations might possibly supplement 

 some of these studies and should, therefore, be presented. 



Meat infusion agar was prepared in the usual way with 1 per 

 cent Witte's peptone and 1/2 per cent sodium chloride in the 

 Arnold sterilizer. It was cleared with egg white, filtered through 

 cotton and titrated to + 1. The medium was sterilized by being 

 heated for three successive days in the Arnold. A stock solution 

 of Victoria blue 4 R. was prepared and the requisite amounts of 

 this were added to comparatively large amounts of the agar to 

 yield 1/20, 1/30, 1/40 and 1/50 per cent respectively of the 

 stains; the required number of plates were poured from each. 

 Hence all the plates containing a given per cent of the stain were 

 uniform in every respect. 



1 



THE JOURNAL OF BACTERIOLOGY, VOL. Ill, NO. 1 



CO 



