and some other Animal Fluids , 
107 
6. Effects of Alkalies on the colouring Principle of the Blood . 
The caustic and the carbonated alkalies form deep red so- 
lutions of this substance, which arc extremely permanent. 
1. Solutions of pure potash, and of the subcarbonate, take 
up a large proportion of the colouring matter of the blood. 
The intensity of the colour of this solution, when concentrated, 
is such, that it appears opaque, unless viewed in small masses, 
or in a diluted state, when it is of a bright red colour. 
2. In soda and its subcarbonate, the solution has more of a 
crimson hue, which colour is extremely bright in its concen- 
trated state. 
3. The solution in liquid ammonia approaches nearer to 
scarlet than that in which the fixed alkalies are employed. 
4. When these alkaline solutions are supersaturated with 
muriatic acid, or with dilute sulphuric acid, they acquire a 
colour nearly similar to the original solutions in those acids, 
which have been above described. 
5. Nitric acid added in small quantities, or even to satura- 
tion of the alkaline menstruum, heightens the colour of the 
three compounds ; but when there is a slight excess, a tint. of 
orange is produced, which soon passes into bright yellow. 
6. The alkaline solutions may be evaporated nearly to dry- 
ness without losing their red colours ; during the evaporation 
of the ammoniacal solution, the alkali flies off, and a brown- 
red solution of the colouring matter in water remains. 
