CHAP. II.] HETERO-ALBUMOSE. 127 



Preparation A (a)^ = 72 *64< 



B (a) D = - 79'05 



' C (a) D = - 77-90 



D (a)j = - 7318 



E(a) I) = -7l -40. 



The following are the means of several analyses of each of five 

 different preparations of proto-albumose (Kuhne and Chittenden). 



Preparation ABODE 



(Mean) (Mean) (Mean) (Mean) (Mean) 



Carbon 5O89 50'39 50'54 51'50 50'55 



Hydrogen 6'83 6'74 6'69 6'80 6'85 



Nitrogen 1712 1712 17'34 1713 17'01 



Sulphur 117 1-07 117 0'94 1-07 



Oxygen 23'99 24*68 24*26 23'63 24'52. 



Hetero- As has been already stated, this body separates from 



aitmmose. the salt solution of the mixed albumoses, during dialy- 



sis, and adheres as a gum-like mass to the walls of the tube dialyser 

 in which the operation is carried on, so that in order to separate it 

 the tubes must be cut open. Hetero-albumose cannot consequently 

 be separated from the proto-albumose solution by filtration, but its 

 collection is rendered more easy if the liquid be saturated with sodium 

 chloride, after which it is separated by decantation. The crude 

 hetero-albumose, thus obtained on drying, assumes the appearance of 

 plates of gelatin. In order to purify the substance, two methods are 

 available ; the first of which consists in dissolving it in 5 or 10 per 

 cent, solution of NaCl, and simply dialysing the solution ; the second 

 consists in precipitating the salt solution just referred to by means of 

 rock salt, redissolving the precipitate, and then dialysing the solu- 

 tion. 



Hetero-albumose is insoluble in pure water, which thereby causes 

 fragments of the substance to soften and swell. Solutions of NaCl, 

 so dilute as to contain less than 0*5 per cent, of the salt, or 

 strong to complete saturation, dissolve hetero-albumose, though 

 slowly, in considerable proportions, though the salt acts most effi- 

 ciently as a solvent in proportions varying between 5 and 10 

 per cent. On completely saturating solutions of hetero-albumose 

 with NaCl, the substance is abundantly precipitated, though precipi- 

 tation is not complete, and on subsequent dialysis, a further precipi- 

 tate is obtained. Strong solutions in 5 to 10 per cent, solutions of 

 NaCl are rendered turbid by the addition of water. 



In addition to neutral salts, dilute solutions of acids, alkalies, and 

 alkaline carbonates, act as efficient solvents of hetero-albumose. 



The solutions, thus obtained, are, in general, precipitated by neu- 

 tralising them, though never completely so, as the substance is held in 

 solution by the salts which are formed during the process. NaCl 

 solutions of hetero-albumose always have a distinctly alkaline re- 

 action. 



