24 PHYSIOLOGICAL CHEMISTRY. 



These modifications, which may be obtained in a solid gelatinous 

 condition by sufficient concentration, are called acid albuminates 

 or acid albumin, sometimes also syntonin, though we prefer to call 

 that acid albuminate syntonin which is obtained by extracting 

 muscles with hydrochloric acid of 1 p. m. 



The alkali and acid albuminates have the following reactions in 

 common : They are nearly insoluble in water and dilute common- 

 salt solutions (see previous page), but they dissolve easily in water 

 after the addition of a very small quantity of acid or alkali. Such 

 a solution or one nearly neutral does not coagulate on boiling, but 

 is precipitated at the normal temperature on neutralizing the sol- 

 vent by an alkali or an acid. A solution of an alkali or acid albu- 

 minate in acid is easily precipitated on saturating with NaCl, but 

 a solution in alkali is precipitated with difficulty or not at all, 

 according to the amount of alkali it contains. The nearly neutral 

 solutions are precipitated by mineral acids in excess, also by many 

 metallic salts. 



Notwithstanding this agreement in the reactions, the acid and 

 alkali albuminates are essentially different, and by dissolving an 

 alkali albuminate in some acid no acid albuminate solution is 

 obtained, nor is an alkali albuminate formed on dissolving an acid 

 albuminate in water by the aid of a little alkali. The alkali 

 albuminates are relatively strong acids. They may be dissolved in 

 water with the addition of CaC0 3 , with the elimination of C0 a , 

 which does not occur with typical acid albuminates, and they 

 show in opposition to the acid albuminates also other variations 

 which stand in connection with their strongly-marked acid nature. 

 Dilute solutions of alkalies act more energetically on albumin than 

 do acids of the same concentration. In the first case a part of the 

 nitrogen, and often also the sulphur, is split off, and from this 

 property we may obtain an alkali albuminate by the action of an 

 alkali upon an acid albuminate; but we cannot obtain an acid 

 albuminate by the reverse reaction. (K. MOEKEK.) 



The preparation of the albuminates has been given above. By 

 the action of alkalies or acids upon an albumin solution the corre- 

 sponding albuminate may be precipitated by neutralizing with acid 

 or alkali. The washed precipitate is dissolved in water by the aid 

 of a little alkali or acid, and again precipitated by neutralizing the 



