v ALBUMOSES AND PEPTONES 187 



free from all admixture, three albumoses, namely hetero-albumose, 

 a-proto- and /2-proto-albumose. He found that pure primary albumoses 

 are precipitated by saturating the solutions with sodium-chloride 

 (Kiihne), or half -saturating them with ammonium-sulphate (Hofmeister), 

 but the second method is more effective. Pick's method of preparing 

 hetero-albumose by three precipitations with ammonium -sulphate 

 solutions and four precipitations with alcohol did not yield Haslam a 

 pure fraction, free from other fractions. On adding an equal volume 

 of alcohol to his primary albumose Haslam obtained two fractions : 



1. One insoluble in cold water, and nearly insoluble in water at 

 60, which he for this reason calls hetero-albumose, after Kiihne. It 

 amounts to rather less than fifty per cent of the fraction insoluble in 

 equal parts of alcohol and water. 



2. Another fraction, fairly easily soluble in water, yielding solutions 

 of a syrupy consistence, and being nearly completely precipitated from 

 its solutions by rather less than an equal volume of alcohol, or byltn 

 equal volume of saturated ammonium-sulphate solution. This fraction 

 is called a-proto-albumose. 



The /3-proto-albumose is characterised by being soluble in equal 

 parts of alcohol and water, at the ordinary temperature, but precipitable 

 by the addition of an equal volume of saturated ammonium-sulphate 

 solution. Haslam's /3-proto-albumose corresponds principally with 

 Pick's proto-albumose. The primary albumoses, as represented by the 

 hetero, the a- and the /3-albumose, all contain tryptophane, for they 

 give the glyoxylic reaction, but only the /3-proto-albumose gives a 

 well-marked red colour with Millon's reagent, while the hetero- and 

 a-proto-albumose give only a deep yellow colour, showing that the 

 tyrosin group is present to a much greater extent in the /5-proto- 

 albumose. 



Peptic-Peptones 



The peptones resulting from peptic digestion Kiihne 1 called 

 ampho-peptones, because he believed them to be composed of the two 

 tryptic-peptones : the anti- and the hemi-peptone. This, however, is 

 not the case, and therefore the term must no longer be used. Sieg- 

 fried 2 and his pupils Miihle, Borkel, and Scheermesser were the first 

 to prepare pure peptic -peptones by precipitating them from a satu- 

 rated ammonium sulphate solution with iron-ammonia alum. 



1 W. Kiihne and R. H. Chittenden, Zeitschr.f. Biol. 22. 423 (1885). 



2 M. Siegfried, Ber. d. deutsch. diem. Qes. 33. III. 3564 (1900) ; Zeitschr. f. 

 physiol. Chem. 38. 259 (1903) ; P. Miihle, Dissertation, Leipzig, 1901 ; C. Borkel, 

 Zeitschr. /. physiol. Chem. 38. 289. (1903) (here is given a detailed description) ; W. 

 Scheermesser, ibid. 37- 363 (1903). 



