ENZYMES OF THE TUBERCLE BACILLUS 133 



AUTOLYTIC ENZYMES 



Method 



The amount of non-coagulable nitrogen was determined in all 

 the following experiments, except where otherwise indicated, by 

 the colorimetric micro-method as devised by Folin and Farmer 

 (1912) using the distillation modification of Bock and Benedict, 

 (1915). The coagulable nitrogen was removed by the addition 

 of ten volumes of 2.5 per cent trichloracetic acid according to 

 Green wald (1915). The results obtained were plotted in curves, 

 using the initial nitrogen found as the zero point, that is the 

 amount of non-coagulable nitrogen obtained in a definite volume 

 (1 cc. of solution) at the beginning of the experiment was sub- 

 tracted from the amount of nitrogen in an equivalent amount 

 (1 cc.) of solution subsequently. 



The method used for determining quantitatively the amount 

 of amino acid a nitrogen was that devised by Harding and Mac- 

 Lean (1915; 1916). Asparagin was used as a standard and since 

 the results are merely comparative the objections to the use of 

 asparagin raised by the above authors did not apply to the 

 procedure. 



EXPERIMENTAL PART 



Series I. Liberation of nitrogenous substances by tubercle bacilli 

 suspended in salt solution 



In order to determine whether there was a liberation of non- 

 coagulable nitrogenous substances from tubercle bacilli under 

 certain conditions, heavy suspensions were made of virulent 

 human tubercle bacilli in sterile physiological salt solution and 

 divided among three graduated centrifuge tubes in as nearly 

 equal amounts as possible (each tube containing 10 cc. of heavy 

 suspension). At the conclusion of the experiment the amount 

 of residual nitrogen remaining in the bacilli was always deter- 

 mined and found to agree fairly well within the limits of error 

 of the method, thus serving as a check upon the use of approxi- 



