632 ME. A.H. CHUKCH ON TITEACIN, AN ANIMAL PIGMENT CONTAINING COPPEE. 
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 unnecessary consti- 
tuent 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 Plantain-eaters remains constant. I will now state what this proportion is. 
In my earliest analysis of turacin I employed a specimen which had been precipitated 
by acetic acid from the alkaline extract of the feathers. Now, on burning some tura- 
cin thus prepared, I found that it left a very considerable amount of ash, nearly twice as 
much as in subsequent experiments where hydrochloric acid had been used as the pre- 
cipitant of the pigment. Some calcium, magnesium, and ferric phosphates had obsti- 
nately adhered to the precipitated turacin, and increased to a marked extent its normal 
quantity of ash. The same salts accompany the colouring-matter of blood with 
similar tenacity. But it was soon found that the new pigment might be obtained in 
such a state of purity as to leave no other ash when burnt than nearly pure cupric oxide, 
the 7 per cent, of phosphates &c. having been previously removed by the action of 
hydrochloric acid without any change in the turacin itself. In the analyses which 
follow, turacin precipitated by hydrochloric acid was employed ; the amount of ash other 
than cupric oxide will be seen to amount to about 1 per cent, only of the substance 
analyzed. I may add that even this residual impurity may be completely removed by 
the further employment of hydrochloric acid. 
Analysis. 
Turacin taken. 
Total ash. 
Ash per cent. 
i. 
•1293 grm. 
•0108 
8-35 
ii. 
•0538 
•0048 
8-60 
Turacin taken, 
corrected for 
CuO obtained. 
CuO per cent. 
Cu per cent. 
ash. 
iii. 
•125 
•0090 
7-20 
5-75 
iv. 
•061 
•0045 
7-38 
5-89 
V. 
•053 
•0040 
7-55 
6-03 
vi. 
•1553 
•0115 
7-41 
5-91 
Some difficulty was experienced in determining the nitrogen contained in turacin. 
The first combustions were made with soda-lime; but attempts to obtain, with the ammonia 
evolved, a satisfactory platinum-salt were unsuccessful. The NH 3 is accompanied by a 
substance which reduces the platinic chloride. More satisfactory and accordant results 
were secured when the ammonia evolved by turacin on combustion with soda-lime was 
received into standard sulphuric acid, and the amount of this acid thereby neutralized 
ascertained by a standard soda-solution. Finally, however, a modification of Dumas’s 
absolute method of determining nitrogen as gas was adopted : the method was as follows. 
The substance, dried at 100°, was burnt with cupric oxide in a combustion-tube 2 feet 
in length, in which was contained, at its remote end, 6-5 grms. of pure sodium bicar- 
bonate. Next to this was a layer of cupric oxide, then the mixture of turacin and 
* Private contribution from J. J. Monteiro, Esq., Dec. 10, 1867. 
