CHAP. II.] DEUTERO-ALBUMOSE. 129 



When boiled with lead acetate and sodium hydrate, a brown 

 precipitate occurs in solutions of hetero-albumose, but this is smaller 

 in amount than would be exacted from the amount of sulphur 

 which the substance contains. 



Copper sulphate, and neutral and basic lead acetates, precipitate 

 solution of hetero-albumose in sodium chloride, and the precipitates 

 are insoluble in excess of the precipitants. 



Unlike p'roto- or deutero-albumose, hetero-albumose in solution 

 is not precipitated by mercuric chloride, whether the reaction be 

 alkaline, neutral, or faintly acid. On addition of acetic acid, however, 

 a precipitate falls which requires a very large excess of acid to dis- 

 solve it. 



Hetero-albumose is laevogyrous, its specific rotation having been 

 found (the mean of three determinations) to be (a.) D = 68'6o. 



The following is the composition of hetero-albumose, according to 

 the analyses of Kiihne and Chittenden : 



Carbon ;. 5074 



Hydrogen 672 



Nitrogen 1714 



Sulphur 1-16 



Oxygen 24'24 



From these numbers it would appear that there is no appreciable 

 difference in ultimate composition between proto- and hetero- 

 albumose. 



Deutero- This body, although present in the mixed 'hemi- 



aibumose. albumose ' product of digestion with pepsin and acid, 



was obtained by Kiihne most easily from ' Witte's Peptone/ which is 

 an article of commerce, and like the majority of other commercial 

 preparations sold under the name of Peptones, contains large quan- 

 tities of the mixed albumoses in addition to hemi- and anti- 

 peptones. 



The mixed albumoses, or Witte's peptone, having been pounded 

 in a mortar with saturated solution of NaCl, and the solution 

 having been filtered, it is treated with acetic acid, which at once 

 throws down an abundant precipitate of deutero-albumose, which is 

 collected in a bag, washed with saturated solutions of NaCl, redis- 

 solved again in weak salt solution, and reprecipitated with acetic 

 acid. The precipitate is again dissolved, the salt and acetic acid are 

 separated by dialysis, the acid with considerable difficulty, and best 

 after having been cautiously neutralised with solution of sodium hy- 

 drate. In the dialyser, the hetero-albumose is found in solution. The 

 latter is concentrated by evaporation, and the hetero-albumose is pre- 

 cipitated by the addition of alcohol ; the precipitate is washed with 

 absolute alcohol and ether and obtained as a perfectly white, light 

 powder, which but for containing a small quantity of calcium sulphate 

 (0'68 177 per cent.) appears to be perfectly pure. 



G. 9 



