1911] iiii Phijsir.iil Clhcnmlrij and tlw. Durlrhio of rjiiiiu/iiifi/. 21.') 



IV'. — The Peptic Digestion, Schutz's Rule, 



The most interesting reaction of this kind is the peptic digestion 

 of all)nniinons snbstances. E. Schiitz found that the (piantity of 

 pepton formed during a given time is proportional to tlic square root 

 of the adopted quantity of pepsin. Later investigations by Sjoquist, 

 Henri, and Bayliss proved that with a constant quantity of pepsin the 

 digested (piantity (i.e. the quantity of pepton) is proportional to the 

 square root of the time of digestion ; or, generally, that the digested 

 quantity is proportional to the square root of the product of quantity 

 of pepsin used and time of digestion. This rule is called Schiitz's rule, 

 after its discoverer. 



It was believed for a long time that this rule was peculiar to 

 the action of organic ferments ; it is also found in the action of 

 trypsin on albuminous substances, and of lipases from the pan- 

 creatic juice, or from castor beans, on fats, as well as for the peptic 

 or tryptic digestion of coagulated albuminous substances, and for the 

 action of proteolytic ferments, e.g. from malt. It had not been found 

 for common chemical processes. Then I proved, theoretically as well 

 as experimentally, that the same rule holds good for the saponifica- 

 tion of esters with great excess of ammonia. The peculiarity depends 

 upon the formation of ammonium salts in the process itself. Accord- 

 ing to the law of mass-action, the acting number of hydroxyl-ions 

 is lowered in a high degree through the presence of the ammonium- 

 ions of the ammonium-salt formed, so that after a short time the 

 number of acting hydroxyl-ious is very nearly inversely proportional 

 to the quantity of salt present. In this case Schutz's rule holds good 

 as indicated by a mathematical analysis of the process, and experiments 

 verified this conclusion. But the calculation indicates that this rule 

 should not be applicable further than until about 50 per cent, of the 

 ammonia is consumed, and it is easy to deduce the general law for 

 the whole process. The same was found to be the case for the 

 action of the examined ferments of organic origin. Thereby it was 

 proved that these phenomena depen'd upon an interaction between 

 the products of decomposition and one of the reacting substances 

 of such a nature that the really active part of that substance is in- 

 versely proportional to the quantity of reaction-products formed. The 

 antigenes or ferments have also in this case their analogies in general 

 chemistry. 



The mathematical analysis of these cases shows that the decom- 

 posed quantity is only dependent on the magnitude of the product 

 q.t, where q is the quantity of ferment used and t is its time of action. 

 These processes are therefore monomolecular. 



Cases have been observed in which the reaction-products do not 

 exert this influence upon the reacting substances. The reacting 

 substances were in this case of a relatively low molecular weight, but 



