70 Intelligence and Miscellaneous Articles, 



it retains its glutinous state. With the mineral acids it forms a glu- 

 tinous compound, insoluble in water, until the excess of acid is re- 

 moved, and it is then as perfectly precipitated from this solution as 

 from that in vinegar, when more acid is added. The phosphoric 

 acid is however an exception, for it does not precipitate the acid so- 

 lutions. Vegetable gelatine also combines with the caustic alkalies, 

 and when the gelatine is in excess, a solution is obtained, which is 

 so perfectly neutral that no alkaline taste remains. It gives by eva- 

 poration a transparent mass, which is again soluble in water, which 

 leaves undissolved the greater part of the viscid principle. Ammonia 

 and lime-water precipitate vegetable gelatine from solution in acids, 

 and redissolve it j but if it be aggregated these alkalies do not dis- 

 solve it, or at least the solution is slowly effected. With the earths 

 and. the metallic oxides, vegetable albumen forms insoluble com- 

 pounds ; the alkaline carbonates precipitate vegetable albumen from 

 solution in the caustic alkalies or in the acids. The precipitate is a 

 compound of the gelatine with the alkali, which without the liquid is 

 not gelatinous. The persulphate of iron does not precipitate vege- 

 table gelatine from solution in vinegar. On the contrary, it is pre- 

 cipitated from its acid solutions by the ferrocyanate of potash, in a 

 hard, white, semitranspafent mass, which is deposited on the sides 

 of the vessels. It is also precipitated from solution, either in acid or 

 alkali, by the permuriate of mercury and tincture of galls. The ge- 

 latine, in the solid state, is tanned in the two solutions, exactly like 

 animal gelatine. The viscid principle, which has been several times 

 mentioned, has not had its properties examined. The best method 

 of separating it is to treat vegetable gelatine with concentrated vine- 

 gar, and when the mass is thoroughly penetrated, to mix it in the cold 

 with weak alcohol, which dissolves the acetate of gelatine, and the 

 undissolved matter is also to be washed with cold weak spirit. It 

 dries into a colourless transparent body, which yields ammonia by 

 distillation. It swells in alcohol and becomes viscid ; when heated in 

 it, solution takes place, but it is precipitated on cooling. 



Vegetable albumen, when dissolved to saturation in weak alkaline 

 solutions, possesses in so great a degree the properties of white of 

 egg, that, as is well known, it has been mistaken for it. Its solution 

 in potash, when the latter is not in excess, has no alkaline taste 

 whatever. It coagulates slightly by ebullition, but it is generally 

 retained by the alkali ; it combines with acids. The solution when 

 perfectly saturated is soluble in water, but an excess of acid precipi- 

 tates it j vinegar and phosphoric acid, however, are exceptions to this, 

 for they may be added in large quantity, without occasioning precipi- 

 tation. Before treatment with potash, vegetable albumen when boiled 

 in alcohol dissolves sparingly in vinegar or phosphoric acid ; but 

 when boiled with these acids, it forms a transparent jelly, which is 

 colourless and bulky. With permuriate of mercury, tincture of galls, 

 and ferrocyanate of potash, it acts like animal albumen. 



The French chemists have considered the azotized principle con- 

 tained in emulsive seeds as analogous to cheese in milk. Soubeiran 

 has shown that this principle in almonds, similar to that which has 



been 



