Evening star. [volume] (Washington, D.C.) 1854-1972, 1902-02-08
THE EYES OF iMALS
POINTS OF SIMILARITY IN MEMBERS
OF MAMMALIAN ORDER.
Scientific Investigations Conducted in
the Geological Gardens of
European Cities.

From the London Chronicle.
One of the most remarkable scientific in
designations of modern times is now beng
brought by DR.. Lindsay Johnson, +. r. c.
S., to the close of its earliest stages. 1t
is some years ago now since the DOCTOR
bordering certain appearances-called the
..fuudus oculi'-at the back of the human
eye began TO wonder whether monkeys
possessed the peculiar spot in the center
of vision known as the ''macula lutea, or
yellow spot-the part of the eye in man
which is used in reading.
He betook himself to Jamrach's collec-
ton Of animals and other menageries, and
found with establishment that all the mon
keys did possess that spot as in man, but
that it varied with each genus. Following
up this clue, he discovered that every
family of the mammalian order possessed
a distinct appearance of its own in the eye,
by which any one seeing the back OF the
eye with an ophthalmoscope and light
would be able to recognize not only the
family, but the genus of the animal.
Examining Animals.
He then proceeded Systematically to ex-
anime all the animals to be seen in the
geological gardens of London, Antwerp.
Amsterdam, Hamburg and elsewhere and
as a result of this gigantic labor he found
he realized that certain organs. such as
the pecteh, which sticks out from the op-
tic nerve inside the eye of all birds without
exception. and of certain reptiles, was also
to be found in large number OF the lower
animaIS-rodents and marSupialS. IhfS or
itself was an interesting piece of evidence
in support of the Darwinian doctrine or
evolution: but the doctors various discov-
cries are to be found recorded in the pro-
ceedings of the Royal Society.
His method of invest eating, however. mas
not been yet recorded, and this to the gem
eral public will be the more interesting por-
ton of the story of his work 10 examine
the eyes of the animals it was necessary for
DIR. Johnson to darken the cage, TO sit be-
side the animal with a lamp behind his head
and to look through the ophthaimoscope at
distance of half an inch from the animals
eye, for a period of not less than two hours
at a time. The total time spent over each
animal would vary from eight to sixteen
hours. He examined the eyes of about
thousand animals, and made drawings of
about 80. some fifty of which have SO far
been published by the Royal Society.
Handling Elephants.
In cases of the larger animals it was, of
course. necessary to confine their move
ments. Thus the elephants We're chained
down. Sacks some eight feet long were
made for slipping over the bears. which
We're then confined in them with ropes.
The closed ends of the sacks were next slit
with a knife. and az Bruin protruded his
head he was promptly muzzled and lifted
on to the table for the eye testing.
In the cases of lions. leopards, tigers and
large eats muZzleS could not be used,
they frightened the animals nearly to
death. and the doctor had therefore to re-
sort to private menaseries, where the
beasts were less wild. Here he found it adj
viSable to cut off the whiskers of the
brItes, as the touching of the whiskers dur
ing the examination made them snap.
The resourcefulness of the doctor and his
assistants had to be endless. Some of the
birds Were induced to thrust their bills into
large coTks. and the fishes had to be treated
very gingerly to avoid their suffoca ton
The boa-constrictors and pythons were
thrown into sacks, to circumvent their
squeezing properties and their heads We're
held out of the sacks by the keepers; while
with wolves, beavers. offers. seals and sea
lions nets were thrown over them, and they
were twisted in the meshes.
There was no resort to chloroform. The
doctor found that oaXing and patience
with the great majority of the animals rem
dered unnecessary the use of artificial
means of inducing quiet, and 1t was only
with the larger beasts that nets, ropes and
bags Were employed.
DR.. johnson is now busy with the micro
scopical and mathematical side of his work
leading up to the whole theory Of vision,
and is preparing another paper to submit to
the Royal Society.
Snow as a Purifier of Atmosphere.
From the Chicago Record Herald
THE beautiful snow" has a grander mis-
sion nowadays than to stir the poet to ioc-
unG jinglas. 1t is an emblem Of purity and
health in a deeper sense than Is conveyed
by its aspect OF milky whiteness 1t Is an
evangel Of good health because it holds
down millions of microbes and retards the
growth of new ones In Crhica on r. doas