EXPERIMENT STATION BULLETINS. 



351 



greater change iu a few minutes than the other caused in many weeks. 

 Nevertheless, the form of the two enzymic curves is much alike, if drawn 

 to comparable scales. The data for this curve are taken from the experi- 

 ments of VanSlyke, Harding and Hart (cited in Lafar, Handbuch, Band 

 IJ, p. 149). 



ACTION OF GALACTASE IN MILK. 



Age of jSIilk. Soluble Nitrogen. 



Fresh 9.33% of total nitrogen. 



7 davs 11.77% " " 



21 "* 15.91% " " 



49 " 21.59% " " 



112 '' 32.82%, '' " 



192 " 37.63% " " 



These three curves demonstrate that there is very little difference iu 

 the purely chemical and enzymic processes, as far as the form of 

 curves is concerned, though their mathematical equations are quite dif- 

 ferent. It is impossible to decide by the picture of the curve alone 

 whether we are dealing with an enzyme or with the law of Guldberg and 

 Waage. 



Quite different from these cun-es are the changes produced by grow- 

 ing and multiplying organisms. The difference is mainly, and in most 

 cases only, the increase of the active mass in these processes. The 

 simplest illustration is the following: 



An acid-producing bacterium is inoculated into a sugar solution. In 

 the time required by these bacteria to double their number, a certain 



Fig. 3. The Action of Galactase in Milk. 



