1867.] Dr. Thudichum on the Colouring -matter of the Urine. 217 



nitric acid (cholocyanine) , of which the peculiar spectrum was determined. 

 A great number of green, blue, violet, and red bodies can be produced by 

 appropriate agents, which, if they could be obtained on a large scale, might 

 find technical application. 



II. On Biliverdine or Cholochlorine and its Cojnpounds. 

 Sect, i treats of the mode of obtaining biliverdine. Cholophseine is dis- 

 solved in carbonate of potassium, and warmed while a current of air is 

 passed through it. When the solution is green, it is precipitated with 

 hydrochloric acid. The precipitated biliverdine is easily soluble in alcohol. 

 Sect. 2 describes the physical properties of biliverdine, as a non-crystalline 

 splendidly green substance, the solution of which gives no particular absorp- 

 tion phenomena in the spectrum. Sect 3 gives the elementary analyses and 

 theory of biliverdine, which led to the formula 0^ Hg NO^. Thus it was 

 shown that it originated from cholophseine by the addition of oxygen and 

 subsequent subtraction of carbonic acid. 



Sect. 4. treats of the compounds of biliverdine. The calcium-salt was not 

 obtained pure. The barium-salt appeared to be G^^ H,. Ea N3O., and was 

 precipitated by baryta-water from an alcoholic solution of biliverdine. It 

 consequently consisted of one atom of the neutral salt with an atom of 

 biliverdine and one of water. Lead and copper compounds were also ob- 

 tained. No insoluble silver-salt could be obtained. The addition of oxide 

 of silver to an alcoholic solution caused a reaction, consisting in an oxida- 

 tion of the biliverdine. 



A new reaction for biliverdine is stated. When dissolved in alcoholic 

 ammonia, and boiled with an ammoniacal solution of silver nitrate, silver is 

 deposited, and on addition of an acid a splendid purple matter is produced 

 (bilipurpine). 



Of these new substances and others the author hopes to treat in future 

 communications. 



Chlorine and other substitution-products are also mentioned. 



The foregoing contributions will make the chemistry of the bile in the 

 main complete. Human bile contains cholophseine, but most commonly 

 by the side of it bilifascine, a brown substance to be treated of hereafter. 



Second Series. — The Chemical Nature and Composition, Combina- 

 tions and Metamorphoses of the Colouring-matter of the Urine. 



I. On Uromelanine, a product of decomposition of TJrochrome. 

 In the Hastings Prize Essay for 1864 the author described a substance 

 to which he gave the name of Uromelanine, on account of its origin and 

 black colour. He now describes the method of obtaining it from putrid 

 urine as well as fresh, and a method of purification by which it is obtained 

 of uniform composition and in a pseudo-crystalline condition. 



