86 



CHR. BARTHEL 



As is obvious, this is a manifestl^^ acid solution. The possi- 

 bihty that here was the explanation of the failure to obtain 

 growth with Bad. vulgar e now seemed vei'y probable to me. 

 An investigation of this question was therefore undertaken, 

 which I wish to present in this paper. I have also attempted 

 to answer another question, namely, whether or not it is neces- 

 sary to have both asparagine and ammonium lactate present in 

 the solution. 



The researches, after a series of orientation expermients, which 

 need not to be given here, were carried out in the following 

 manner: 500 cc. of the tryptophane solution, but without 



TABLE 1 



ammonium lactate, was divided into two portions of 250 cc. 

 each. To one of these was added 1.25 grams (0.5 per cent) 

 ammonium lactate. Each one of these solutions was divided 

 into two parts, of which one was left as it was, while the other 

 was neutralized with n NaOH to litmus. All of these four 

 solutions were then transferred to test tubes (10 cc. per tube). 

 From each of these foui- solutions, Jena glass tubes were also 

 made up for compaiison. The pH was determined in all the 

 solutions before and after sterilization, which was carried out in 

 the autoclave at 118°C. momentarilj'-. The results of these 

 series are shown in table 1 . 



From the table it is seen that the solution itself is very acid, 

 where it is not neutralized, and almost without exception the 



