Colour-change in Feathers



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straight and close together to a height of 130 to 150 feet, finally spreading

out with superb branches. Everywhere enormous climbers force them¬

selves upwards to hang down again like giant snakes ; Aroidce, orchids,

ferns, and, above all, Bromelias garnish the trunks and branches,

whilst from the ground rise everywhere palms and tree-ferns,

and various plants with red and yellow blossoms ( Iieliconias,

Ravenalas, etc.).


Contrary to what is generally supposed, the undergrowth of the

Guiana forests is not often entangled, and one can easily travel through

it; the one inconvenience is caused by the numerous patches of soft

mud and stagnant water which one has constantly to traverse and where

one may easily be engulfed. The surface of the ground is a succession

of mounds and marsh, cut up by creeks.


{To be continued.)



COLOUR-CHANGE IN FEATHERS


A very interesting article from the pen of our Australian member,

Mr. G. A. Heumann, appeared in Aie Australian Zoologist of 17th May,

1922, of which the following is an extract:—


“ In the same way as the food will influence the construction and

activity of the animal cell, so it must have an influence upon the kind

and the effect of the chemical colour matter. I need only mention the

different colours of the canaries which can be produced as red, white,

brown, etc. If cayenne pepper is mixed with the food for young

canaries the result is red canaries, but if this food is given at a later

period, that is to say when the birds are feathered, then only the down

and small feathers will show the colour-change, as only these will be

moulted out during the first moult, the larger feathers for the time

being remain unchanged, for the reason that this feather is meanwhile

dead and the matter changes within the body have ceased. This

example is proof that foodstuffs materially influence the coloration

of feathers, and I am of opinion that in this way the chemical colours

may not only be maintained but also strengthened and improved,

but of the ways and means in detail, how to achieve this are so far

a closed door to me.


“ One fact I have settled to my entire satisfaction, and that is that



