214 Notice of some Recent [March 



excess of albumen, but insoluble in an excess of chloride 

 of mercury. If the precipitation is produced by an excess 

 of chloride of mercury, the solution passing through depo- 

 sits by evaporation crystals of chloride of mercury, which 

 have a yellowish colour,from some dissolved albumen, but 

 very inconsiderable in quantity. 



In ammonia the moist precipitate is soluble, but after 

 some time the solution becomes muddy, and is increased by 

 the application of heat. 



In potash the moist precipitate dissolves easily, the solu- 

 tion depositing gradually black metallic mercury. 



By acetic acid also the precipitate is dissolved, and is not 

 altered by boiling. Sulphate of copper added to the solu- 

 tion produces a green, and chloride of iron a yellowish 

 brown precipitate. 



According to Bostock, the precipitate is a combination 

 of the constituents of muriate of mercury with albumen, 

 but Orfila considers it a compound of albumen and chloride 

 of mercury, as its solution was coloured black by a free al- 

 kali. This, however, was no proof, because all organic 

 substances which are not volatile, reduce mercury from 

 oxide of mercury or solution of chloride of mercury, when 

 a free alkali is present. 



From the experiments of F. Rose, it appears that this 

 precipitate is not a combination of chloride of mercury with 

 albumen, but of albumen with the oxide of mercury. The 

 same result took place with the serum of the blood. A 

 solution of the red matter of the blood yielded with an ex- 

 cess of the chloride of mercury a red precipitate, which 

 consisted of a combination of the colouring matter with 

 oxide of mercury, albumen, and sulphated protoxide of 

 copper. 



An excess of a solution of sulphate of copper completely 

 precipitates albumen of a green colour, which is dissolved 

 by an excess of albumen. Ammonia dissolves the precipi- 

 tate, forming a dark blue solution. Potash produces a vio- 

 let solution. A solution of carbonate of soda dissolves it 

 completely, occasioning a violet colour. Potash throws 

 down the copper, but in the filtered liquid no sulphuric 

 acid can be detected. 



If the precipitate is heated and dissolved in nitric acid, 



