According to Ulbricht, the methylmercapto-compound referred in the title is said to antagonize to vitamin B_6,espeoially to pyridoxamine in the culture of vitamin B_6 requiring mutant of E. coli or to antagonize to the pyrimidine moiety of thiamine in the culture of a mutant of several bacteria. In this connection the authors attempted to see whether some antagonism exists between the above two compounds also in mice which were injected with the methylmercapto-compound. But no competition was found. The toxicity of the thiomethyl compound was rather weak.