200 EXPERIMENTAL OBSERVATIONS ON 



converted in equal times) at two different concentrations of enzyme 

 Cj and c 2 , then " Schiitz's law " is that 



The law has been most worked out in the case of pepsin by 

 E. Schiitz, J. Schiitz, Huppert and J. Schiitz, and Borissow; but 

 according to Pawlow and his co-workers, using Mett's method, it 

 also holds for the tryptic and diastatic enzymes of the pancreas, 

 in addition to pepsin. 



The whole subject, however, deserves to be thoroughly worked 

 out anew, for there is a want of concordance in methods and results 

 amongst the different workers, who have not only employed different 

 methods and different stages in the reaction for different enzymes, 

 but also for the same enzyme. Thus in the case of trypsin Bayliss 

 finds, as stated above, that the law at any rate for dilute solutions 

 is approximately a linear one, while Pawlow, using a different 

 method (Mett's), finds the " Schiitz law " followed. Again, while 

 Huppert and J. Schiitz found the Schiitz law followed for not too 

 concentrated solutions on using dissolved proteid (egg albumin), 

 they found with the Mett's tube method on coagulated egg albumin, 

 that this law was not obeyed, but rather that the length of albumin 

 dissolved was nearly directly proportional to the concentration in 

 enzyme. On the other hand, Borissow, using the Mett's method, 

 found that pepsin in its action in dissolving coagulated egg-white 

 obeyed Schiitz's law. 



In the writer's own experience with the Mett's method, and 

 active preparations of commercial pepsin of various origin, the 

 Schiitz's law is by no means followed. With stronger solutions, the 

 length of egg-white dissolved off is approximately equal; as the 

 concentration in enzyme is diminished, the intensity of action falls 

 off very slowly, much less than in direct linear proportion, but there 

 is no period at which the Schiitz law is closely obeyed, and with very 

 dilute solutions the length of egg-white is so little as not to be 

 accurately measurable, so that the method is useless for testing 

 very dilute solutions. Even in stronger solutions the slowness of 

 fluid diffusion in the narrow tubes tending to accumulation of 

 products of digestion at the active interface, and the irregularity with 

 which the column of egg-white is eaten away, form grave objections 

 to the employment of this oft- described method. 



