DIGESTION. 187 



comes swollen and transparent and partly dissolved. If at this time 

 the solution be carefully neutralized, the dissolved portion can be 

 regained in the form of acid-albumin or syntonin a fact which in- 

 dicates that the first effect of the gastric juice is the acidification of the 

 proteids. This having been accomplished, the pepsin becomes opera- 

 tive, and in a varying length of time transforms the acid-albumin into 

 a new form of proteid, termed peptone, of which, as indicated by 

 chemic tests, there are probably two forms antipeptone and hemi- 

 peptone. This form of proteid differs from all other forms of proteid 

 in being soluble in both acids and alkalies and non-coagulable by 

 heat. In the transformation of acid- albumin into peptones it is 

 possible to isolate by the addition of ammonium sulphate inter- 

 mediate bodies to which the term albumoses or proteoses has been 

 given, and which differ somewhat in their solubility. The albumoses 

 are termed, in the order in which they make their appearance, 

 primary and secondary. Inasmuch as two forms of peptone can be 

 isolated after complete digestion of any given proteid, it is assumed 

 from this and other facts that their appearance has been preceded by 

 two forms of albumose. This supposed change is represented by 

 the following scheme: 



Albumin 

 Acid-albumin 

 Proto-albumose = = Heter - album se 



Deutero-albumose = Deutero-albumose 



Peptone (Ampho-peptones) . Peptone. 



From the fact that one form of peptone, under the influence of the 

 pancreatic ferment trypsin, can be decomposed into leucin, tyrosin, 

 aspartic acid, etc., it is believed that all the simple proteids contain 

 two distinct groups or radicles, termed hemi and anti groups, and 

 that it is this fact which determines the line of cleavage and the char- 

 acteristics of the cleavage products. The two forms of peptone, 

 hemipeptone and antipeptone, are frequently included under the term 

 ampho- peptones. 



Nearly all forms of proteid are in a similar manner transformed 

 into peptones by gastric juice. Beyond this stage, however, there 

 does not seem to be any further change, peptones apparently being 

 the final products of gastric digestion. The intimate nature of this 

 change is practically unknown, but there are reasons for thinking 

 that it is a process of hydration, attended by cleavage, with increasing 

 solubility of the resulting products. 



