180 



Protein is in the same condition as many other organic radicals, 

 which though not isolated as yet, are nevertheless acknowledged 

 or assumed to exist. 



The Protein substances behave in general like Protein (con- 

 taminated with sulphur); in their composition they only differ 

 from it sometimes by a larger amount of sulphur, sometimes by 

 an additional amoiint of phosphor; but in all instances they 

 contain cei'tain inorganic salts, notably phosphate of lime, and 

 therefore leave, when incinerated, an ash, the quantity of which 

 often amounts to 10%. 



Prussic Aci(l=HYDiiocYANic Acid. 



Pseiwlocurariu. As to distribution see Oleandi-in. Boil the 

 solution of tannate of Ps. obtained in the preparation of olean- 

 drin, with oxyd of lead, evaporate the filtrate almost to diyness, 

 remove from it the oleandrin by ether, dissolve the remnant in 

 alcohol and evaporate the filtrate. The residue is Pseudocurarin. 

 —A yellowish gum-like amorphous mass without smell or taste; 

 most readily soluljle in water and in alcohol, not in ether; forms 

 Avith acids salts which do not crystallise ; is not precipitable by the 

 chlorides of platinum or of mercury. Acts not poisonous. 



Psei«lom01'l)lliu=:C34 H19 NOs + 2 HO. In Opium. Is 



best obtained by connecting its preparation with that of morphin 

 after the well known method of Ilobei-tson-Gregory (see Codein). 

 By adding to the purified mixture of the chlorides of morphin — 

 codein, etc., in alcoholic solution, a small excess of ammonia, the 

 Ps. remains dissolved, while only the morphin is thrown down. 

 Saturate the solution, freed from the morphin, with a slight excess 

 of hydrochloric acid, distil ofi' the alcohol and strain the remaining 

 solution through a coal filtei-. The solution, which is now com- 

 l)letely cleai', but mostly coloiu'ed, yields, on neutralising with 

 diluted ammonia, a voluminous deposit, consisting chiefly of Ps., 

 which has to be collected, washed and dissolved in acetic acid. 

 Add to the filtered solution carefully as much diluted ammonia as 

 enables the licjuid, after the precipitation, to redden very slightly 

 l>lue litmus-paper. By this oj^eration the Ps. subsides, which by 

 combining with hydrochloric acid, yields a well-crystallising salt, 

 which is purified by re-crystallisation in water. Finally dissolve 

 the purified salt in much hot water and decompose by ammonia.— 

 Fine, crystalline deposit, suspended in a liquid of a vivid, silky 

 lustre, insoluble in water, alcohol, ether, chloroform, sulphide of 

 carbon, diluted sulphuric acid, and in solutions of carbonate of 

 soda, readily soluble in potash and soda-ley, and also a little in 

 milk of lime, slightly in liquor of ammonia, readily in alcoholic 

 ammonia; is of neutral reaction, does not saturate the acids, is 

 tasteless in its combinations; dissolves in concentrated sulphuric 

 acid, with olive-green colour, in concentrated nitric acid with 



