and some other Animal Fluids. 
lol 
ing the coal left after the destructive distillation of albumen, 
did not contain any appreciable proportion of iron. 
Assuming the existence of iron in the colouring matter of 
the blood, I made the following experiments upon the crassa- 
mentum of that fluid. 
Two pints of blood were collected in separate vessels. The 
one portion was allowed to coagulate spontaneously, the other 
was stirred for half an hour with a piece of wood, so as to 
collect the coagulum, but to diffuse the principal part of the 
colouring matter through the serum. These two portions of 
coagulum were now dried in a water-bath, and equal weights 
of each reduced in a platina crucible to the state of coal, which 
afterwards was incinerated. The ashes were digested in dilute 
nitro-muriatic acid, and the solution saturated with liquid am- 
monia, in order to precipitate the phosphate of lime as well 
as any iron which might have been present. 
The precipitates were collected, dried, and treated with 
dilute acetic acid, by which they were almost entirely dis- 
solved, some very minute traces only of red oxide of iron 
remaining, the quantity of which was similar in both cases? 
and so small as nearly to have escaped observation. 
It is reasonable to infer, that if the colouring matter of the 
blood were constituted by iron in any state of combination, 
that a larger relative proportion of that metal would have 
been discoverable in the former than in the latter coagulum ; 
but frequent repetitions of these experiments have shewn that 
this is not the case, and the following result appears to com- 
plete the evidence on this subject. 
The colouring matter of a pint of blood was diffused by 
agitation through the serum, from which it was allowed 
