40 Transactions of the 



under investigation. Some idea may be formed of the intimate 

 union subsisting between the copper and the other consti- 

 tuent elements of the colouring matter, from the observation, 

 that Turacin dissolved in oil of vitriol, and re-precipitated by 

 excess of sodium acetate, suffers by this treatment no loss of 

 copper. 



' The different parts of eighty- seven red feathers of Cory- 

 thaix alhocristata have been carefully examined. From the 

 red barbs of these a considerable quantity of Turacin vpas 

 prepared, vrhile theu' shafts were submitted to special dis- 

 section. The clear, horny parts, or quills proper, at the 

 base of each feather, were cut off and separately incinerated ; 

 so also were the upper parts or shafts of the eighty-seven 

 feathers, and in like manner, the membranes found in the 

 quills. There was no copper in the ash of the eighty-seven 

 quills and none in that of the membranes ; but a very mmute 

 trace was recognised in the ash of the shafts. There is 

 therefore no possibility of any mistake having occurred as to 

 the copper present in the red parts of the feathers of the 

 Touracous. It cannot have been introduced in any pre- 

 servative solution, for it would then be found in the black 

 parts of the web, as well as in the red ; it cannot be an 

 artificial dye, for birds bred in captivity acquire the cupreous 

 pigment naturally ; ' it cannot be an accidental and un- 

 necessary constituent of the red colouring matter ; for not 

 only is it impossible to remove this metal from the pigment, 

 but the proportion of copper present in the Turacin obtained 

 from different species of Plantam-eaters remains constant 



' Notwithstanding the diversity of origin and certain 

 changes in the mode of preparation, the analytical results 

 have been remarkably concordant. 



' Affinities of Ttiracin. — In its colour, in its absorption- 

 spectrum, and in some of its other characters, Turacin cor- 

 responds closely with the scarlet Cruorin of blood, yet it 

 contains no iron, or, at most, an inappreciable trace of this 

 metal. Iron, however, exists to the extent of between six 

 and seven per cent, in hsematin, the chief derived colouring 

 matter obtained from the blood, and is doubtless a con- 

 stituent of the original Cruorin ; yet if, in Turacin, the iron 

 of Cruorin is replaced by copper, there are other and wider 

 differences of composition and deportment between the two 

 pigments, which prevent us from regarding Turacin as a 



' Private contribution fiom J. J. Monteiro, Esq., Dec. 10, 1867. 



