i©4 Mr, W. Brande s Chemical Researches on the Blood , 
5. Effects of Acids on the colouring Matter. 
A. Muriatic acid poured upon the colouring matter of the 
blood, renders one portion of it nearly insoluble and of a 
bright brown colour : another portion is taken up by the acid 
forming a dark crimson solution when viewed by reflected 
light ; but when examined by transmitted light, it has a 
greenish 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 permanent. 
Infusion of galls produces no change in this muriatic solu- 
tion, nor is its colour affected by carbonated alkalies, even 
when added in considerable excess. 
It is rendered brown red by supersaturation with caustic 
potash, but not with soda, nor 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 
$oo°. In three or four hours the acid was poured off, 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 w 7 ater~ 
bath, to dryness ; it retained its colour to the last, and left a 
