led in the Tarentino by eating _hypericum criscum_, while
black sheep escape; white rhinoceros are said to perish from eating
_euphorbia candelabrum_; and white horses are said to suffer from
poisonous food where colored ones escape. Now it is very improbable
that a constitutional immunity from poisoning by so many distinct
plants should, in the case of such widely different animals, be always
correlated with the same difference of color; but the facts are
readily understood if the senses of smell and taste are dependent on
the presence of a pigment which is deficient in wholly white animals.
The explanation has, however, been carried a step further by
experiments showing that the absorption of odors by dead matter, such
as clothing, is greatly affected by color, black being the most
powerful absorbent, then blue, red, yellow, and lastly white. We have
here a physical cause for the sense-inferiority of totally white
animals which may account for their rarity in nature. For few, if any,
wild animals are wholly white. The head, the face, or at least the
muzzle or the nose, are generally black. The ears and eyes are also
often black; and there is reason to believe that dark pigment is
essential to good hearing, as it certainly is to perfect vision. We
can therefore understand why white cats with blue eyes are so often
deaf--a peculiarity we notice more readily than their deficiency of
smell or taste.--_Dr. Wallace, British Association_, 1876.

* * * * *

IMPROVED TROLLING HOOK.

Mr. Henry C. Brush, of Brush's Mills, N.Y., has patented through the
Scientific American Patent Agency an improved troller, the novel
feature in which consists in attaching a float to the shank of the
implement under the revolving blade, the object being to keep the
troller near the surface of the water, where the fish may see it more
readily, and whereby the liability of catching in weeds and logs is
obviated.

[Illustration]

A is a float, attached to the shank, _a_, of the troller. B is the
spoon, which is swiveled in the usual manner. The device is very
simple, and is claimed to prevent all the annoyance arising from the
hook catching in sunken obstructions.

* * * * *

PURIFICATION OF WOOL AND WOOLEN STUFF.

The process, patented some time ago, for the removal of straw, burrs,
etc., from wool, by treatment with sulphuric acid, has been modified
by Lisc as follows: The