JOHN H. NORTHROP 



237 



inhibition of the solution containing a small amount of trypsin will 

 be greater than in that containing a larger amount of trypsin. Second 

 the trypsin is constantly becoming irreversibly inactivated. The 

 amount of this inactivation is proportional to the time and is therefore 

 proportionately greater in the dilute solutions since these require a 

 longer time to cause the change used as the end-point. This effect 

 is much more noticeable at a higher temperature, as would be expected. 



TABLE I. 



Both these effects are in the same direction and both become more 

 noticeable the longer the hydrolysis proceeds, as Bayliss^ found. 

 The experiment was made in duplicate and was run with intermediate 

 trypsin concentrations which are not plotted. Table I gives a sum- 

 mary of the whole experiment. The table shows that the values 

 found for the amount of trypsin are within about 10 per cent of the 

 expected values over the entire range of the experiment and much 

 closer for smaller variations of the trypsin concentration. This dif- 



