MR. A. H. CHUECH ON TURACIN, AN ANIMAL PIGMENT CONTAINING COPPER. 631 
nitrogen, and oxygen, in what proportions I shall presently state. It contains no sulphur. 
The ash or non-volatile constituents of the new pigment have also been submitted to a 
careful examination. 
Turacin may be dried at 100° without change ; but at a considerably higher tempera- 
ture its surface-colour alters, becoming bluish and then a dull green. Afterwards it 
shows some symptoms of fusion, giving off a violet vapour resembling that of iodine ; it 
finally burns away, leaving a greyish-black ash. 
The close resemblance of turacin to cruorin induced me to test at once, in the ash of 
the new colouring-matter, for iron, the characteristic metallic constituent of the pigment 
of the blood, and of its derivatives. The ash of turacin was dissolved in nitric acid, 
excess of sodic acetate added, and then potassic ferrocyanide. Much to my surprise, 
instead of the deep blue ferric ferrocyanide, a copious purple-brown precipitate of cupric 
ferrocyanide made its appearance. Not only was copper present, but there was so much 
of it that it could be detected by its spectrum when the ash of a few red barbs of the 
original feathers was moistened with strong hydrochloric acid and exposed on a platinum- 
wire to the flame of a Bunsen burner. 
This detection of copper in the colouring-matter was so extraordinary that it became 
necessary to sift the matter thoroughly. The idea that a preservative solution containing 
copper had been used in dressing the skins of the birds suggested itself ; but this notion 
was soon proved untenable ; for there is no copper in any part of the skin save in the 
red feathers, and in these feathers themselves the presence of copper is strictly confined 
to the red barbs. Even barbs that are partly red and partly black contain no copper in 
their black parts, and abundance in those which are red. Moreover, as acids do not 
wash out the copper from the feathers, and the most severe chemical treatment, short of 
actual destruction of the pigment itself, does not remove it from the prepared and pure 
turacin, it is evident that this metal, copper, is an integral constituent of the substance 
under investigation. Some idea may be formed of the intimate union subsisting between 
the copper and the other constituent elements of the colouring-matter, from the observa- 
tion that turacin, dissolved in oil of vitriol and reprecipitated by excess of sodium acetate, 
suffers by this treatment no loss of copper. 
The different parts of eighty-seven red feathers of Corythaix albocristata have been 
carefully examined. From the red barbs of these a considerable quantity of turacin 
was prepared, while their shafts were submitted to special dissection. 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 minute trace was recognized 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 intro- 
duced in any preservative solution, for it would then be found in the black parts of the 
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