17 



Ueved from DE HAEN'S statement, that blood 

 contained glue, of that kind which is produced 

 when bones or cartilages are boiled with water ; 

 but I have proved that glue is not found within 

 the animal body, and that DE HAEN, and all 

 after him, have considered as glue, the albumen, 

 in a half coagulated state. Among the imme- 

 diate constituent parts of the blood, some authors 

 have even counted sulphur, because blood, when 

 evaporated in silver vessels, blackens the silver. 

 This conclusion, however, is incorrect, because the 

 sulphur has belonged, as a constituent part, to the 

 albumen, and has been disengaged through the 

 combined destructive effect of boiling, and of the 

 caustic alkali, on the albumen. DEYEUX and 

 PARMENTIER believed that the red colour of 

 the blood was a solution of iron in the free alkali 

 of the blood. FOURCROY and VAUCIUELIN en- 

 deavoured to prove, that it was a solution of red 

 subphosphate of iron* in albumen. They found 

 that albumen, or serum, which was triturated witli 

 this subphosphate before it was dry, dissolved it, 

 and assumed itself a red colour, and that this red 

 colour was still more heightened by caustic alkali. 

 According to these experiments, the colouring of 

 the chyle in the air consisted in the change of the 

 phosphate of iron, from a neutral phosphate of the 



c 



