196 Chemical Properties of Animal Fluids. [Sept. 



blood was a solution of red subphosphate of iron in albumen. 

 We shall find that neither of these theories can be true, and 

 that the mode in which the iron is combined with the colour- 

 ing matter will probably long remain unknown. 



The colouring matter dried, and exposed to fire in an open 

 crucible, melts and swells up, and at last burns with flame. It 

 leaves behind a porous coal, which cannot be incinerated with- 

 out the greatest difficulty. For this purpose it must be reduced 

 wi" T C1 T i P owder > and exposed to the fire in very thin layers. 

 While the charcoal is consuming, it continually exhales a smell 

 ol carbonate of ammonia, which proves that the constituents of 

 ammonia are not disengaged from the charcoal by heat alone, 

 but that the influence of oxygen is also required in order to 

 effect the separation. The ashes remaining after the destruction 

 ol the carbon are yellow and pulverulent. 



The disengagement of ammonia from a mass of burning 

 charcoal which has already been exposed for a long time to fire, 

 is undoubtedly a very remarkable phenomenon; but another and 

 a no less singular fact is presented by the same substance. If the 

 charcoal which has already been long burning, and whose surface 

 is covered with yellow ashes, be pulverized and boiled in nitro- 

 munatic acid, the acid dissolves the ashes already formed, but 

 does not deprive the remainder of the charcoal of the property 

 ol affording a fresh quantity of ashes on re-exposure to the fire. 

 These observations seem to prove that the carbonaceous matter 

 of the colouring substance which remains after the flame has 

 ceased to appear, and after the whole mass has been subjected 

 to a strong red heat, cannot be, as was before supposed, a me- 

 chanical mixture of charcoal with the phosphates and carbonates 

 of the earths and of iron. We must therefore consider it as a 

 chemical compound of carbon, phosphorus, sulphur, with cal- 

 cium, ammonium, and iron ; and it appears that it is in a mode 

 analogous to this combination that the iron as well as the cal- 

 cium, phosphorus, &c. are united with the charcoal, and other 

 constituents of the colouring matter ; for it is very evident that 

 the mode in which bombustible bodies combine with one an- 

 other, and with a small portion of oxygen in organic sub- 

 stances, is totally different from that which prevails among the 

 inorganic productions of nature. 



To return to the ashes of the colouring matter ; water extracts 

 from it a very small quantity of soda mixed with muriate of 

 soda. I have great reason to suspect that these two constituents 

 arc merely accidental, and that they appear in consequence of 

 the impossibility of freeing the crassamentum entirely from 

 serum. If the alkaline liquor which is obtained from the ashes, 

 be saturated by acetic acid, evaporated to dryness, and again 

 dissolved, a precipitate will appear on the addition of lime- 



