130 



EDWIN O. JORDAN 



MINIMUM LYTIC DOSE, B. subtilis. 



Lactose, on the other hand, is distinctly favorable to the formation of 

 the enzyme. 



MINIMUM LYTIC DOSE. 



The addition of glycerin (2.0 per cent) to C did not give as a rule 

 quite as strongly lytic nitrates as lactose, but the difference was not 

 as great as that between lactose and dextrose. 



In the lactose medium, E, the M. L. D. was determined as follows : 



* This was more strongly lytic than any broth or gelatin culture of this organism observed in the 

 course of any experiment. 



t This amount produced only partial liquefaction. 



These observations show that in relatively simple synthetic media 

 certain bacteria can produce large amounts of gelatinase, amounts in 

 fact that are quite as great as those produced in broth or gelatin media. 

 This is true, however, as a rule only when growth continues for a long 

 period. The latter fact probably explains the failure of observers to 

 discover the occurrence and extent of enzyme formation in non-proteid 

 media. 



Reaction of medium. The influence of the reaction of the cul- 

 ture medium upon enzyme production is advantageously studied in 

 the case of such an organism as B. pyocyaneus. As is well known, 



