Occasional Notes. 139 
of extermination all along the line even to the very nest. 
Sprinkled in the openings of the nest, the crystals would 
naturally have a still more marked effe6t. Coal-tar was 
also effe6lively used to break the course of a track. 
Necessarily, constant attention is required, so that 
remedial steps should be taken before the mischief is 
done. Le jeu vaut la chandelle. 
Natural and Artificial Coloration in Birds. — My at- 
tention has recently been directed by Mr. E. E. H. 
FRANCIS to a note in the Pharmaceutical Journal, June 
1869, on the occurrence of the pigment turacine in the 
red feathers of certain " Plantain-eaters " (Musaphagidae), 
through which a considerable amount of light is thrown 
on the alterations by artificial means of the colours of 
the feathers of living birds — a subject already discussed 
by Mr. 1M THURN in a previous volume of Tirnehri.* 
The pigment turacine, discovered by Prof. CHURCH, is 
obtained from the feathers of several species of " Plan- 
tain-eaters ", by treating the red barbs with weak caustic 
soda, which dissolves it out. The dissolved pigment is 
precipitated by hydrochloric acid, and, when washed and 
dried, presents the form of dark scales having a red-violet 
colour. It is remarkable in the fa6l that it possesses a 
definite and constant proportion of the metal copper in its 
constitution. The proportion is 5*9 per cent, of copper; 
and this amount is constant in the turacine derived 
from different species, and cannot be due to any ac- 
*■ Timehri, vol. III., p. 355. 
S 2 
