and some other Animal Fluids. 183 



It may be employed In a more concentrated state ; but 

 the bright colour of the solution is in that case apt to be 

 impaired, and when more largely diluted with water, its 

 fiction is slow and uncertain. ' Either the sediment of the 

 colouring matter from the serum, or the crassamenlum of 

 the blood, may be indifferently employed in forming these 

 solutions. 



When dilute sulphuric acid is added to the colouring 

 matter, it renders it slightly purple; and if no heat be ap- 

 plied, the acid when poured off and filtered, is colourless; 

 so that dilute sulphuric acid when cold, does not dissolve 

 this colouring principle. 



One part of the crassamentum of blood cut into pieces, 

 was put into a matrass placed in a sand heat, with about 

 three parts of dilute sulphuric acid. It was kept for twelve 

 hours in a temperature never exceeding 2l'2°, nor below 

 100^. After twenty-four hours the acid was filtered off, 

 and it exhibited a beautiful bright lilac colour, not very 

 intense, and tcinted with green when viewed by trans- 

 mitted light. 



This solution is nearly as permanent as that in the mu- 

 riatic acid. Some of it which has been kept for a month 

 in an open vessel, often exposed to the direct rays of the 

 sun, is very little altered. 



When diluted with two or three times its bulk of water, 

 the lilac tint disappears, and the mixture is only slightly 

 green. 



When exposed to heat, the colour gradually changes as 

 the acid becomes more concentrated by evaporation, and 

 when reduced to about half its bulk the lilac hue is de- 

 stroyed. 



The solutions of pure and carbonated alkalies when added 

 in excess, convert the colour of this sulphuric solution to 

 brownish red; but in smaller quantities, they merely impair 

 it by dilution. 



C. Nitric acid, even much diluted, is inimical to the co- 

 Jouring mailer of the blood. 



A few drops added to the muriatic or sulphuric solutions 

 gradually convert their colour to a bright brown, and larger 

 quantities produce the same change inimcdiately. 



The action winch this acid exerts upon the colouring 

 matter under other circum'^lances is nearly similar, and al- 

 ways attended with its deeomposilion, so that my attempts 

 to procure a red solution in this menstruum uniformly 

 failed of success. 



p. Acetic acid dissolves a considerable quantity of the 

 M 4 colouriiJg 



