484 



excellent growth could be noted, and after a couple of days positive 

 tryptophane, and tyrosine-ieactions of the sediment. 



The present investigation, therefore, shows clearly (hat there are 

 bacteria in llie paunch of the cow, capable of building up trypto- 

 phane and tyrosine with an aliphatic nitrogen-compound and with 

 ammonia. With every one of the six paunclies we succeeded in 

 obtaining this result. 



We consider the presence of tyrosine to be established when 

 bacterial bodies show a phenol-reaction (Mitj.on's) The non-specificity 

 of the tryptophane reactions is of no importance in our experiments. 

 They are only needed to show the piesence of an indole-derivative so 

 long as tryptophane is considered as sole indole-derivative in the 

 protein-molecule ^). 



Positive results were also obtained in the experiments in which 

 asparagin (or sodium- aspartate) had been replaced by urea. The 

 bacterial growth was, however, decidedly slower. The ammonium- 

 lactate had been substituted in these experiments by potassium 

 lactate, so that urea was the sole source of nitrogen. 



After 2 X 24 hours the tryptophane-reactions were as a rule weak 

 in the turbid culture solution and very clear in the sediment, which 

 had been obtained through centrifugation. 



A couple of times we added tryptophane to the Uschinsky solution 

 which resulted in the formation of indole contrary to the other 

 experiments. 



Direct addition of indole inhibited bacterial growth considerably; 

 it was arrested completely by 50 mgms per 100 c.c. 



Whether tryptophane can be developed from indole, as assumed 

 by LoGiE, is not borne out by the present experiments, for, where 

 addition of a small quantity of indole caused some bacterial growth, 

 the formation of tryptophane may have resulted from the presence 

 of ammonium-nitrogen or asparagine-nitrogen. 



When substituting glucose for the glycerol and the lactic acid of 

 the UscHiNSKY-solution a tryptophane synthesis takes place which is 

 almost equal to that in the ordinary UscHiNSKY-solution. 



In experiments under approximately anaerobic conditions the growth 

 was inferior to that obtained in the manner above-described. An 

 experiment, in which air was drawn through the fluid by suction, 

 did not yield a larger growth than usual. 



1) Since gelatine does not yield Voisenet's, nor Millon's reaction and proline 

 and oxyproline are contained in it, it follows that these two' amino-acids do not 

 give these reactions. 



