310 A CHEMICO-PHYSIOLOGICAL STUDY Of 



Neumeister * and others have shown, however, that when this 

 crucial test is applied to the specific proteoses formed in 

 gastric digestion, for example, there is invariably an admix- 

 ture of the so-called hemi and anti groups ; not an equal mix- 

 ture, for protoproteose is apparently composed in great part 

 of hemi groups with only a small admixture of anti groups, 

 while heteroproteose is made up chiefly of anti groups, as 

 judged by the behavior of the respective bodies toward trypsin. 

 In the amphopeptone of gastric digestion, on the other hand, 

 we have apparently a commingling in equal proportion of 

 hemi and anti groups, for if this substance is digested for some 

 tune with a vigorous pancreatic juice, approximately one half 

 breaks down into crystalline decomposition products, leaving a 

 residue of peptone resistant to the further action of trypsin, 

 t. e., an antipeptone. How far these terms hemi and anti are 

 to be considered as representing real differences in chemical 

 constitution is very uncertain. It may be that the differences 

 are more apparent than real, and that the characteristic 

 behavior toward trypsin is the result of more or less super- 

 ficial peculiarities. Granting that this is so, the terms still 

 have significance as indicating physiological differences of 

 some moment and are thus of value. Certainly the view at 

 one time suggested that an anti body contained no aromatic 

 groups capable of yielding tyrosin under any conditions is not 

 tenable. To be sure, a pure antipeptone gives little or no 

 Millon's reaction, but antialbumid boiled for some time with 

 10 per cent sulphuric acid will yield considerable tyrosin, 

 although when acted upon by an alkaline solution of trypsin 

 no tyrosin whatever results. Thus, Dr. Alice H. Albro, 

 working in this laboratory with antialbumid made from coagu- 

 lated egg-albumin, found on boiling the substance with 10 per 

 cent sulphuric acid for 80 hours that 2.7 per cent of tyrosin 

 was formed, together with considerable leucin. In this con- 

 nection it will be remembered that Erlenmeyer and Schb'ffer 

 obtained 1 per cent of tyrosin by boiling egg-albumin with 

 sulphuric acid, while Schiitzenberger obtained 2.0 per cent by 



* Neumeister, Zeitschr. f Biologie, 1887, xxiii, p. 380. 



