172 THE PROCESSES OF DIGESTION AND RESORPTION. 



Until quite recently it was thought that peptic activity ceased 

 with the formation of amphopeptone, in the sense of Kiihne, and 

 that other nitrogenous decomposition-products beyond those already 

 considered were not formed during this process. In the light 01 

 modern investigations, however, this view can no longer be upheld, 

 for it has been shown that in a very early stage of digestion 

 already, and before the formation of peptones and the deutero- 

 albumose-C, at least, a very considerable portion of the albuminous 

 nitrogen is split off in the form of substances which no longer give 

 the biuret reaction. It is known, moreover, that the greater portion 

 of the final decomposition-products which result from the action of 

 pepsin do not consist of either albumoses or peptones, but appar- 

 ently of these same bodies which do not give the biuret reaction. Of 

 their nature, however, and their mode of origin, nothing is known. 



From what has been said, it is thus clear that the peptic disinte- 

 gration of the albuminous molecule is very much more complicated 

 than was formerly supposed, and much w r ork must still be done 

 before we can form a clear idea of the entire process. 



As regards the extent to which peptic digestion is carried in the 

 stomach, our knowledge is likewise not complete, but there is reason 

 for the assumption that ordinarily the process does not extend beyond 

 the formation of the primary albumoses. We find, as a matter of 

 fact, that while these appear within the first half-hour of digestion, 

 the secondary albumoses, in experiments in vitro at least, are not 

 formed until after the second hour, beyond traces, and it is to be 

 noted that a more energetic formation in fact does not occur within 

 the period of time during which remnants of an ordinary meal are 

 usually found in the stomach. We are thus forced to the conclusion 

 that if a more extensive decomposition of the albumins is necessary 

 before resorption can take place, this must occur in the small 

 intestine under the influence of the pancreatic juice. But we may 

 also suppose that the epithelial lining of the gastric mucosa can 

 bring about the further transformation of the primary albumoses 

 of itself. We know, as a matter of fact, that in the resorption of 

 the albumins, as in that of the carbohydrates, the epithelial cells 

 play an active part, and that absorption by osmosis under normal 

 conditions can scarcely enter into consideration. We have seen, 

 moreover, that an inversion of polysaccharides to monosaccharides 

 can thus be effected, and we have reason to suppose that a digestion 

 of albumins also can be accomplished in the same manner. It is 

 even claimed that a resorption of native albumins can take place in 

 the absence of the proteolytic ferments, and that, unlike the poly- 

 saccharides, solutions of such albumins can be injected directly 

 into the blood-current without causing albuminuria. We have seen 

 that the presence of the disaccharides in the blood at once leads to 

 their elimination, and that the body is manifestly incapable of caus- 

 ing their inversion and further transformation into glycogen when 

 they are present as such. As the introduction into the blood-current 



