io8 Mr. W. Brande’s Chemical Researches on the Blood , 
Having ascertained the above facts respecting the colouring 
principle of the blood, I next proceeded to examine how far 
it was susceptible of entering into those combinations which 
are peculiar to other varieties of colouring matter. 
These experiments I shall detail in the order in which they 
were made. 
1. Some pure alumine was added to a concentrated aqueous 
solution of the colouring matter of the blood, and after twenty- 
four hours the mixture, which had been frequently agitated 
during that period, was poured upon a filter, and the residuum 
washed with hot distilled water. 
The filtrated liquor had lost much of its original colour \ 
the alumine had acquired a red tinge ; it was dried at a tem- 
perature between 70* and 8o°, during which it became brown. 
2. Two hundred grains of alum were dissolved in four 
fluid ounces of a solution of the colouring matter, similar to 
that employed in the last experiment. The colour of the com- 
pound was bright red. Liquid ammonia was added, and the 
precipitate collected, and carefully dried. It was of a dirty red, 
and after some days exposure to light, became nearly brown. 
From these, and other experiments which I have not thought 
it necessary to detail, it appears that alumine will not form a 
permanent red compound with the colouring principle of the 
blood ; I was therefore next induced to employ oxide of tin.. 
3. Fifty grains of crystallized muriate of tin (prepared 
by boiling tin filings in muriatic acid, and evaporating the 
solution), were dissolved in four ounces of the solution of 
colouring matter, which immediately assumed a purple tint^ 
and became afterwards brown. It was diluted with twice its 
bulk of water, and put aside in a stopped phial. On examin- 
