64



A moot question.



observed by Verreaux and many others since that during heavy rains

these birds descend from the higher branches of the trees and seek

shelter in the lower and thicker undergrowth to avoid the wet, but

that, notwithstanding this, their plumage often becomes so saturated

with moisture that they are quite unable to fly and they can then be

caught with the hand. At this time the greater part of the red

colouring-matter of the wings has become washed out. The same

effect can be produced artificially by rubbing the feathers with soapy

water, when they can be reduced to a dull white or grey colour.

The bird, moreover, has the power of renewing the turacin of the

wings, and very shortly after the plumage becomes dry the colour is

as brilliant as ever. Turacin was carefully analysed by Professor

Church, and was found to contain, in addition to the usual carbon,

hydrogen, nitrogen and oxygen, about 7 per cent, of copper—a

substance not usually found in organic compounds, and never in

such large quantities. Many suggestions have been put forward as

to whence the bird derives this metal, but it is probable that the

presence of small quantities of it in plantains, bananas and other

fruits on which these birds feed is sufficient to account for the matter

without having recourse to suppositions about their swallowing

grains of malachite and other copper ores as has been suggested.”


In experiments undertaken by E. H. U. Draper (‘ Journ.

South African Orn. Un.,’ vol. iv, p. 130), it was found that caustic

soda, 1 per cent., was the most satisfactory reagent for extracting

the colour from the feathers.


In their delightful ‘ Sketches of South African Bird-life,’

p. 108, Messrs. A. Ilaagner and B. H. Ivy say : “ The peculiar part

of the red colouring matter of the wings is that it contains a large

amount of copper (about 7 per cent.), originally analysed by Professor

Church. A friend of ours, a chemist of the dynamite factory, con¬

firmed the copper content of the feathers, hut with regard to the

theory that the red can be washed out with soap and water we are

sorry to say we cannot confirm this in toto. It certainly does get

paler during wet weather and in old skins, but we have never seen it

wash out in nature, and have tried to do so artificially with soap and

water, but without result.”


(To be continued.)



