334 



ARTIFICIAL DIGESTION OF PROTEIDS. 



digestion goes on as before. Any means that prevent the proteid bodies from 

 swelling up, as by binding them firmly, impede digestion. Slightly over half a 

 pint of cold water does riot seem to disturb healthy digestion, but it does so in 

 cases of disease of the stomach. Copious draughts of water and violent muscular 

 exercise, disturb digestion ; Avhile warm clothing, especially over the pit of 

 the stomach, aids it. Menstruation retards gastric digestion. 



[The action of gastric juice on proteids may be observed outside the 

 body, and we can prove, as is shown in the following table, after 

 Rutherford, that pepsin and an acid e.g., hydrochloric, along with 

 water are essential to the formation of gastric peptones : 



The fibrin is obtained by beating blood, and afterwards washing and 

 boiling it to destroy any traces of pepsin. The fibrin may be coloured 

 with carmine, and from the rapidity with which the fibrin is dissolved 

 i.e., the depth of the colour of the fluid we may estimate the 

 digestive power of the gastric juice. Similar experiments may be 

 made with unboiled white of egg, mixed with nine volumes of water, 

 and filtered through muslin.] 



[In all animals gastric digestion is essentially an add digestion, and 

 between the native proteid, fibrin, albumin, or any other form of 

 proteid, and the end-product peptone, there are many intermediate 

 substances and bye-products, whose properties and characters have still 

 to be investigated. If the peptones be decomposed, small quantities of 

 leucin and tyrosin are produced. W. Roberts obtained a bitter 

 substance during gastric digestion.] 



II. Action on other Constituents of Food. 



Milk coagulates when it enters the stomach, owing to the precipitation 

 of the casein, and in doing so, it entangles some of the milk globules. 

 During the process of coagulation, heat is given oft' (Mosso, Ad. 



