24 Chemical Properties of Animal Fluids. [July, 



whatever be the nature of this change induced on fibrin by the 

 alkalies, the former is by no means converted, as M. Fourcroy 

 has alleged, into a fatty substance with which the alkali produces 

 a saponaceous compound, nor has it even the least analogy to 

 any species of soap. As far as I can perceive, this effect of 

 alkalies is confined to the epidermoid textures, and parts which 

 by long and continued boiling are converted into a similar sub- 

 Stance. 



Of the Colouring Mailer and its Chemical Properties. 



In order to separate, as much as possible, the colouring matter 

 from the albumen and the salts of scrum, I cut the crassamen- 

 tum into very thin slices, which I placed upon blotting paper, 

 till it had taken up all that it could absorb: after which they 

 were dried. A portion of the crassamcntum treated in that 

 manner was triturated with water as long as it appeared capable 

 of acting as a solvent. This water acquired from the matter it 

 had dissolved a brown colour of so deep a shade that it did not 

 exhibit the least transparency when contained in a glass tube of 

 a quarter of an inch in diameter. The fluid had a faint odour of 

 blood, and a mawkish, saline, and highly nauseous taste. 



I coagulated the solution by means of heat in a pneumatic 

 apparatus. The mass frothed considerably, but no elastic fluid 

 was disengaged. While yet hot, it was placed on a filter : the 

 liquor had a red colour which it lost by cooling, and at the same 

 time deposited a small quantity of the colouring matter. 1 shall 

 revert to this liquor in the sequel. 



The dark brown coagulated nratter, after being carefully 

 washed, and subjected to a powerful press, was dried at a tem- 

 perature of 7^° (158° Fahrenheit). It was but little con- 

 tracted by the exsiccation, but had become black, hard, diffi- 

 cultly pulverisable, and showed a vitreous fracture. Before the 

 desiccation is complete, it is of a dark brown colour, has little 

 cohesion, and forms a granulated mass: circumstances by which 

 it may be distinguished from both fibrin and albumen. 



1. The colouring matter is acted upon by boiling water in 

 nearly the same way as fibrin, becoming somewhat contracted 

 by coction ; and the solution contains soda, and an animal matter 

 perfectly analogous to that which is obtained from fibrin, but 

 rather less in quantity: for it would appear that a portion of this 

 substance begins to be formed from the commencement of the 

 process of coagulation. It retains its black colour, but loses the 

 propei ty of softening, and dissolving in acetic acid. 



2. Alcohol aud ether convert the colouring matter in part into 

 . a fatty adipoc-iious mass, having a very disagreeable odour. 



3. In au-lic acid the colouring matter immediately becomes 

 eoft, forming a black and tremulous jelly, which dissolves in 



