28 PHYSIOLOGICAL CHEMISTRY. 



tated either by picric acid or by potassium-mercuric iodide and 

 acid. The primary albumoses are completely precipitated by 

 phospho-molybdic or phospho-tungstic acid, while the secondary 

 are not quite completely precipitated, and the true peptones very 

 incompletely. The peptones are also precipitated by mercuric 

 chloride in neutral solutions, and also by tannic acid in liquids con- 

 taining acetic acid. This precipitate may be dissolved in an excess 

 of tannic acid (SEBELIEN"). 



The study of the albumoses and peptones, as above indicated, 

 has undergone in the last few years an essential transformation. 

 It may still be doubtful whether the behavior of a single salt, the 

 ammonium sulphate, yields sufficient basis for the characterization 

 of two groups of albuminous bodies, the albumoses and peptones ; 

 and this question is warranted since, according to NEUMEISTEE, we 

 have a deuteroalbumose (found in the pepsin digestion) which is 

 not completely precipitated by ammonium sulphate. It seems that 

 the transformation of albumins into peptones takes place through a 

 number of intermediate steps such as starch undergoes in passing 

 from dextrine into glucose. A complete separation of these several 

 intermediate products, as well as their purification, is an extremely 

 difficult task. 



What relationship do the albumoses and peptones bear to the 

 albumin from which they are formed ? HEBTH has found that 

 fibrin albumose and fibrin have a similar constitution. KUHKE 

 and CHITTTENDEIJ, as also CHITTE^DEN" and his pupils, have ana- 

 lyzed the different albumoses from fibrin, globulin, egg-albumin, 

 myosin, and casein, and found in a few albumoses an increase 

 and in others a decrease in the amount of carbon, nitrogen, and 

 sulphur as compared with the mother-albumin. From the results 

 of their analyses it has been found that, with the probable excep- 

 tion of the peptone standing closest to the albumoses, the difference 

 in the constitution of the original albumins and the corresponding 

 albumose is sometimes in one direction and sometimes in another, 

 and is unessential. 



According to the analyses of peptones (in the old sense) made 

 by MALT, HERTH, and HEKNINGEB, they seem to have the same 

 constitution as the albumin. According to the analyses by KUHNE 

 and CHITTE^DEK of "true" fibrin peptone, part amphopeptone 



