COLOURING MATTERS. 43 



the blood of the vertebrata, and is apparently identical, or 

 nearly so, with the yellow colouring matter described by 

 Sanson.' 



It may be distinguished by its solubility in water, alcohol, 

 and ether, and by the intense brown -red colour that it com- 

 municates to its alcoholic solution. When exposed to heat on 

 a platinum spatula, it does not melt, but develops ammoniacal 

 vapours, burns with a clear flame, and leaves a very trifling ash, 

 which is perfectly free from peroxide of iron. Marchand 

 remarks that hsemaphsein is nothing more than hsematin 

 modified by an alkali, just as O'Shaughness/s suhruhrin, and 

 Golding Bird and Brett's chloroJuematm and xantliohcRmatm 

 are products of the action of nitric acid on hsematin.'- 



c. Hcemacijanin, or a blue colouring matter, has been detected 

 by Sanson in healthy blood, by Lassaigne and Lecanu in the 

 blood of icteric patients, and by Chevreul in the bile. Simon 

 never succeeded in detecting it. For the method of isolating 

 it, and for a description of its chemical characters we must 

 refer to Sanson's paper. It is sufficient to remark that it is 

 described as being insoluble in water, alcohol, and ether, but 

 sHghtly soluble in boiling alcohol, from which, however, it 

 separates on cooling. On the addition of ammonia to its 

 alcoholic solution, a green colour is evolved, but on the addition 

 of an acid, the blue colour is restored. It contains no iron. 



II. THE BILE. 



a. The most important colouring matter of the bile is that 

 to which it owes its characteristic brownish yellow tint. It is 

 termed cholepyrrhin by Berzelius, and bilvphcein by Simon. 

 We shall adopt the latter term. On the gradual addition of 

 nitric acid to a fluid that contains this substance in solution, 

 a very characteristic series of tints are evolved. The fluid 

 becomes first blue, then green, afterwards violet, and red, and 

 ultimately assumes a yellow or yellowish brown colour. 



1 Journal de Pharmacie, Aout 1835, p. 420. 



2 The cliscoverj' of the true nature of subrubrin is due to Drs. Brett and Golding 

 Bird, who showed that it is merely haematin mixed -with a little albumen. Their 

 chlorohaematin is haematin partly oxidised by nitric acid, as Marchand observes ; and 

 their xanthohamatin is at present supposed by Dr. G. Bird to be identical Mith some 

 of the products of the oxidation of protein recently described by Midder. 



