26 PHYSIOLOGICAL CHEMISTRY. 



acetic acid and potassium ferrocyanide, nor by neutral salts and 

 acid. 



The reactions and properties which the albumoses and peptones 

 had in common were formerly considered as the following: They 

 give all the color reactions of the albumins, but with the biuret test 

 they give a more beautiful red color than the ordinary albumin. 

 They are precipitated by ammoniacal lead acetate, by mercuric 

 chloride, alcohol, tannic, phospho-tungstic, phospho-molybdic acids, 

 potassium-mercuric iodide and hydrochloric acid, and lastly by 

 picric acid. The albumoses and peptones have also a greater 

 diffusive power than native albuminous bodies, and the diffusive 

 power is greater the nearer the questionable substance stands to 

 the final product, the so-called pure peptone. 



These old views have undergone an essential change in the last 

 few years. After HEYNSIUS' observation that ammonium sulphate 

 was a general precipitant for albumin, also peptone in the old 

 sense, KUHKE and his pupils proposed this salt as a means of sepa- 

 rating albumoses and peptones. Those products of digestion which 

 separate on saturating their solution with ammonium sulphate are 

 considered by KUHNE and indeed by most of the modern investi- 

 gators as albumoses, while those which remain in solution are called 

 peptones or pure peptone. This pure peptone is formed in rela- 

 tively large amounts in the pancreatic digestion, while in the pepsin 

 digestion it is only small in quantity unless after prolonged diges- 

 tion. 



According to SCHUTZEN BERGER and KUH^E the albumins yield 

 two chief groups of new albuminous bodies when decomposed by 

 dilute acids or with proteolytic enzymes; of these the anti group 

 shows a greater resistance to further action of the acid and enzyme 

 than the other, namely, the hemi group. Corresponding to these 

 views KUHNE divides the albumoses into two chief groups, the 

 antialburnoses and liemialbumoses, and the peptones into two chief 

 groups, the' antipeptoms and the liemipeptones. In the pepsin 

 digestion we obtain, besides different albumoses, a mixture of anti- 

 and hemipeptone, which mixture KUHNE called ampliopeptone. 

 In the digestion with trypsin (the proteolytic enzyme of the pan- 

 creas) the hemipeptone is further split into leucin, tyrosin, and 

 other substances, while the antipeptone remains unchanged. Only 



