mysterious and^not understood by the 
wisest people. 
The material of a feather consists of 
cells that push each other out to their 
destination. They change their forms as 
they travel along, and their colors and 
degrees of hardness change with their 
going. They are composed of about 
the same stuff that makes horns and 
hoofs. Your finger nail is like a 
feather in its growth and composition. 
It is mostly albumen with some lime in 
it. Albumen is the substance which 
makes the white of eggs. 
When the Mexican motmot trims his 
two tail feathers with his beak, he 
merely makes diamond cut diamond. 
The material of the cutting instrument 
is the same as that of the thing cut, 
only somewhat harder. 
When you consider how a feather 
grows by pushing out its cells you must 
wonder at the intelligence which guides 
the cells to change their nature so as 
to form the quill, the shaft, the after- 
shaft, the barb, the barbules, and the 
little hooks which hold them together. 
More than this is the cause for admira- 
tion seen in the regular change of pig- 
ment contained in the cells, so the 
feather shall have its beautiful colors 
and accurate markings. 
Along with the materials of the 
feather is carried a little oil which 
turns the water from the duck's back 
and gives the feather its gloss. It 
is thought by some that the fading of 
feathers in museums where mounted 
[ specimens are exposed to the action 
i of light is largely due to the loss 
! of this delicate oil. No enterprising 
I Yankee has come forward yet with a 
! patent for restoring this oil and giving 
back to the thousands of musty and 
dusty skins in our museums their origi- 
j nal brilliancy. 
Every one wonders at the way feath- 
I ers keep their shape instead of getting 
I hopelessly ruffled. The little hooks 
j which hold the barbules together are 
exceedingly strong and flexible. They 
will yield and bend, but never break. 
Even when torn apart from their hold 
they can grasp again so as to restore 
the injured feather to its former shape. 
VISION AND SCENT OF VULTURES. 
REV. R. T. NICHOL. 
To the Editor of Birds and All Nature: 
Sir: Are you not mistaken in the 
assertion in your October number that 
vultures, carrion-crows, etc., have such 
keen scent that they can detect car- 
casses and offal at a very great dis- 
tance? 
I was under the impression that 
Wilson* had decided this forever, and 
proved conclusively that their appar- 
ently miraculous power of discovering 
their proper food, was due to keenness 
of vision, and not of the sense of smell. 
The following extracts may be new 
to some and interesting to all of your 
♦When 1 said " Wilson" above I find I was slightly 
mistaken. I remembered reading 1 it long ago in 
the first edition I possessed of this writer's works— 
the little four-volume set edited by Prof. Jameson for 
"Constable's Miscellany," Edinburgh, 1831. and taking- 
down the book now, which I have not opened for years, 
I find the passages in question (Vol. iv, pp. 245 et seg.) 
form part of an appendix drawn from Richardson 
and Swainson's '• Northern Zoology," and that the 
real authority is Audubon. 
readers: Under the head "Vultiir aura, 
Turkey Vulture," etc., I find: 
"Observations on the supposed power 
which vultures such as the turkey 
vulture, are said to possess of scent- 
ing carrion at a great distance. 
"It has always appeared to us unac- 
countable that birds of prey, as vul- 
tures, could scent carcasses at such im- 
mense distances, as they are said to 
do. We were led to call in question 
the accuracy of this opinion, on recol- 
lecting the observations of some trav- 
elers, who have remarked birds of prey 
directing their course towards dead 
animals floating in the rivers in India, 
where the wind blows steadily from 
one point of the compass for months 
in succession. It was not easy to con- 
ceive that the effluvium from a putrid 
carcass in the water, could proceed in 
direct opposition to the current of air, 
L63 
