CHEMICAL RESEARCHES ON THE ANIMAL FLUIDS^ 31 



lation of the albumen took place ; the liquid pnrt was separ- 

 ated by a filter. No effect was produced upon it by Voltaic 

 electricity, nor did infusion of galls occasion any precipi- 

 tation. 



I repeated the first experiment with the addition of twenty Farther test of 

 drops of a solution of isinglass to the serum. The liquid '''' «o™positi- 

 Avhich now separated, after the albumen had been entirely 

 coagulated by the action of electricity, was copiously pre- 

 cipitated by infusion of galls. 



It may be inferred from these experiments, that gelatine It consists of 

 does not exist in the serum of the blood, and that the ^e., l^^^mrn com^ 



. 11 Dined with 



rosity consists of albumen in combmation with a large pro- muchaUcaJi. 

 portion of alkali, which modifies the action of the reagents 

 commonly employed, but which is readily separated by elec- 

 trical decomposition. 



To ascertain whether iron exists in the serum of the blood, Slight traces ©f 

 one pint was evaporated to dryness in a crucible, and gradu- 'fo"'" '^^^ 

 ally reduced to a coal, which was incinerated and digested 

 in muriatic acid, to which a few drops of nitric acid were 

 added; some particles of charcoal remained undissolved; 

 the solution was saturated with ammonia, which afforded a 

 copious precipitation of phosphate of Ume, accompanied with 

 slight traces only of oxide of iron, 



V, Some Experiments upon the Coagulum of Blood, 

 Mr. Hatchett's valuable researches on the chemical con- Coagulum «f 

 fititution of the varieties of coagulated albumon have shown, blood. 

 that this substance varies but little in its properties, whether 

 obtained from the crassamentura of the blood, or from washed 

 muscular fibre, or other sources ; but that the proportion of 

 earthy and saline matter is different in the different varieties*. 

 It will also be remarked, on referring to the dissertatiea 

 which I have just quoted, that the ashes obtained by mcine- 

 rating the coal left after the destructive distillation of albu- 

 men, did not contain any appreciable proportion of iron. 



Assuming the existence of iron in the colouring matter of [pquiry 

 the blood, 1 made the following experiments upon the eras- whether the 



i. r .u t n :j colour of blood 



samentura of that fluid. beowmgto 



Two pints of blood were collected in separate vessels, iron. 

 * Phil. Trans. 1800, p. 384. 



The 



