238 BOTANICAL GAZETTE [SEPTEMBER 
which eventually splits to form carbon dioxide and ammonia. 
From the course of the reaction these authors have devised a 
formula which applies to several enzyme reactions which had 
previously been measured, particularly the: hydrolytic action of 
invertase and lactase. It seems possible that it may prove to be 
generally true that the catalyzer combines in a definite manner with 
the reacting substances. 
LABORATORY OF PLANT PHYSIOLOGY 
Harvarp UNIVERSITY 
