CHEMICAL RESEARCHES ON THE ANIMAL FLUIDS. JQl 



5. Effects nf Acids on the colouring Matter. 



A. Muriatic acid, poured upon the colouring matter of (he The colourin?j 

 blood, renders one portion of it nearly insoluble, and of a matter treated 

 bright brown colour : another portion is taken up by the acid, ^ji^ : "'''"''^"' 

 forming a dark crimson solution when viewed by reflected 

 light J but when examined by transmitted light, it has a green- 

 ish hue. 



This solution remains transparent, and its colour is unim- 

 paired by long exposure to light, either in contact with the 

 air, or when kept in close vessels. At its boiling temperature 

 the colour is also permaneni. 



Infusion of galls produces no change in this muriatic solu- 

 tion, nor is its colour affected by carbonated alkalis, even when 

 added in considerable excess. 



It is rendered brown red by supersaturation M'ith caustic 

 potash, but not with soda, or ammonia : these, and especially 

 the latter, rather heighten its colour. 



When considerably diluted with water its original colour is 

 much impaired, and the green hue, which it always exhibits 

 by transmitted light, becomes more evident. 



In preparing this solution, I frequently employed the coagu- 

 lum of blood cut into pieces, and digested in equal parts of 

 muriatic acid and water, at a temperature between 150'' and 

 200®. In three or four hours the acid was poured olT, and 

 filtrated. The clear solution was in all respects similar to that 

 above described, although before filtration it appears of a dirty 

 brown colour. 



I evaporated a portion of this muriatic solution in a water- 

 bath, to dryness j it retained its colour to the last, and left a 

 transparent pellicle upon the evaporating basin, of a dirty red 

 colour : this, when redissolved in muriatic acid, acquired its 

 former tint, but the colour of its aqueous solution was nearer 

 brown than red. 



B. Sulphuric acid, diluted with eight or ten parts of v/ater, ^^^ sulphu- 

 forms an excellent solvent of the oolouring principle of the ric : 

 blood. 



It may be employed in a more concentrated state, but the . 

 bright colour of the solution is in this case apt to be impaired ; 

 and when more largely diluted with water, its action js slow 



and 



