138 H. J. CORPER AND H. C. SWEANY 



described by Kober and his colleagues (Graves and Kober, 

 1914; Kober, 1913; Kober and Graves, 1914), a series of experi- 

 ments were carried out in which heavy emulsions of tubercle 

 bacilli were mixed with definite amounts of various substrates 

 (sodium caseinate for trypsin, acid casein for erepsin, acid 

 edestin for pepsin, nucleic acid for nucleases, starch for diastase, 

 sucrose for invertase, and urea for urease). In the majority 

 of cases this method was found impractical, however, on account 

 of the adsorption of the protein substrates by the tubercle bacilli, 

 which made quantitative determinations impossible. In a 

 number of instances this difficulty was, however, overcome by 

 determining the presence of the enzymes in the autolysate where 

 no adsorption occurs and checking their presence by other 

 methods. 



Methods 



The methods used for quantitative nephelometric determi- 

 nation of the various substrates (casein, edestin and nucleic 

 acid) were those described by Kober and his colleagues, the 

 previously cited micro-method of Folin, modified by Bock and 

 Benedict, for determining non-coagulable nitrogen, and the 

 amino acid a nitrogen method of Harding and MacLean. The 

 presence of urease was determined by the aeration method of 

 Folin (Folin and MacCoUum, 1912) and the presence of diastase 

 and invertase by the amount of glucose liberated from starch 

 and sucrose by the recent picramic acid method of Lewis and 

 Benedict (1915) as used by Myers (1916) and Myers and Rose, 

 (1916), for determining the presence of these enzymes in ptyalin 

 and the presence of glucose, sucrose, dextrin and starch in food- 

 stuffs. The quantitative Fehling method proved far too inac- 

 curate and not delicate enough for this purpose. 



Series I. Proteolytic enzyme acting in alkaline solution {trypsin- 



like enzyme) 



Experiment 1. By its presence in the autolysate, (a) In a 

 graduated 15 cc. centrifuge tube was emulsified 2 cc. of human 

 tubercle bacilli and sufficient sterile physiological salt solution 



