184 PHYSIOLOGICAL CHEMISTRY. 



These compounds are relatively much simpler than the Sieg- 

 fried peptones and might readily be derived from them, with 

 separation, at the same time, of still smaller molecules. 



The conception of " end product " in tryptic digestion is 

 evidently a somewhat indefinite one. Certainly in the animal 

 body the digestive cleavage cannot extend to the production 

 of these small molecules which would doubtless be useless for 

 nutrition. What is obtained in artificial digestions depends 

 largely on the time given and the activity of the enzyme em- 

 ployed; the term "end product" is therefore wholly relative. 



TOXICITY OF DIGESTIVE PRODUCTS. 



It has been known for a long time that some of the artificial 

 digestive products when injected into the circulation directly 

 exhibit a marked toxic action. Experiments in this direction 

 have been made mostly on dogs, and the material employed 

 was usually the commercial product known as Witte's peptone, 

 which contains some real peptone with a much larger portion 

 of proteoses. In experimenting on dogs it has been found that 

 500 milligrams for each kilogram of body weight was sufficient 

 to produce a marked decrease in blood pressure. The clotting 

 power of the blood is at the same time greatly impaired or 

 even destroyed. Larger injections may produce death. 



This effect varies with the nature of the peptone used. In 

 the earlier investigations it was assumed that the commercial 

 peptone was a fairly definite product, and in addition, a real 

 peptone. It is now well known that this was not the case, and 

 in repeating the experiments with products made by modern 

 methods it has been recognized that the purified pancreas pep- 

 tone, which is a much more highly converted product than the 

 Witte peptone, is practically inert. The toxicity is apparently 

 due to the 'presence of one or more of the lower albumoses. 

 A large number of experiments carried out by Chittenden and 

 others show the effects obtainable with the different classes of 

 digestion products. The two principal effects, lowering of 

 arterial pressure and delaying or impeding coagulation, are 



