630 ME. A. H. CHURCH ON TURACIN, AN ANIMAL PIGMENT CONTAINING COPPER. 
caustic alkalies are still more effective. Turacin by long exposure to air and moisture, 
or by continued ebullition with water or alkaline liquids, acquires a colour closely re- 
sembling that of chlorophyll. 
Spectrum of Turacin . — If a piece of the red web of a Touracou’s feather be examined 
with a prism, two black bands will be at once perceived about the lines D and E of the 
solar spectrum (fig. 1). These bands correspond to some extent with those of Stokes’s 
red cruorin, but it will be seen (fig. 2) that they are not identical. When an alkaline 
solution of turacin is similarly examined, the bands (fig. 3) are shifted further from D, 
Pig. 1. 
Spectrum of Turacin as it exists in the feathers. 
Pig. 3. Pig. 4. 
while the blue region of the spectrum is less shaded than it is with the original red of 
the feather, or with coagulated turacin precipitated by an acid. When the alkaline 
solution of turacin is dilute, the band near E is very weak ; but when a strong solution 
is employed, both bands became equally intense, and finally almost coalesce, nearly 
obliterating the space in the green between them. No results have attended my attempts 
to produce in turacin, by ferrous or stannous salts, a reduction similar to that obtained 
in red cruorin by the same means. Coagulated turacin in water, and more particularly 
the web of the red feathers, present by transmitted light very nearly the appearance of 
diluted arterial blood to the eye. 
The change in the colour of turacin produced by exposure to air and moisture may 
be traced in the spectrum of the altered substance (fig. 4). The specimen examined had 
been prepared by long boiling of a soda-solution of the original pigment, but it probably 
contained some unaltered turacin. In this modified spectrum a third black band has 
made its appearance in the orange, between D and C. 
Composition of turacin . — The volatile constituents of turacin are carbon, hydrogen, 
