DIGESTION IN THE STOMACH 



687 



method from ' Wrtte's peptone/ a commercial preparation containing 

 proteoses and peptones. 



The following careful analysis of the constituents of protoalburnose and 

 heteroalbumose (or protoproteose and heteroproteose) respectively shows 

 that the different proteoses really correspond to different groupings of the 

 amino-acids making up the original protein molecule : 



RESULTS OF THE COMPLETE HYDROLYSIS OF HETERO- AND PROTOALBUMOSE 



The results obtained by Pick by hydrolysis of these different bodies show 

 that in the breakdown of protein produced by gastric juice there is really 

 a division of the complex molecule into smaller molecules, which are qualita- 

 tively different. Thus of the fractions which he obtained, some contain the 

 greater part of the sulphur originally present in the protein molecule, another 

 contains the greater part of the carbohydrate group, while others are free 

 altogether from the tryptophane group which is responsible for Hopkins' 

 reaction obtainable in the original protein. 



Proceeding from primary through secondary albumoses to peptones, there 

 is probably a continuous diminution in the size of the molecule. During 

 the time which gastric juice has to exert its influence, a maximum, say, of 

 twelve hours, the breakdown of proteins never passes beyond the albumose 

 and peptone stage, and it is in this form that the proteins of the food pass on 

 through the pyloric orifice into the small intestine. 



ACTION ON THE CONNECTIVE TISSUES AND OTHER 

 FOOD-STUFFS ALLIED TO PROTEINS 



COLLAGEN. The connective tissues are made up chiefly of white fibres 

 more or less modified, which consist of collagen. This substance forms the 

 main basis of areolar tissue, of white fibrous tissue, and of bone. On 

 prolonged boiling, it is converted into gelatin. The gastric juice dissolves 



