, 1886-09-14
W FORMS OF LIFE.


Development of the Senses aud the Brain
Some Curious Facts.
Among the lower forms of life the de-
velopment of the senses seems to have
much to do with that of the brain. This
is what might be inferred. for the
impressions made upon the exterior are
the basis for all intelligent action, so
far as these forms of life, at least, are
concerned. We know very little as to
The kin and amount of sense impress
sions which insects. fishes and reptiles
receive. In the creeping things winch
inhabit the water, as well rs the insects,
we presume that the sense of touch IL
considerably developed, and in such as
possess eyes something analogous TO
what we know as sight must be theirs.
In insects'-some varieties at ~least-sight
must be mar~velously acute, and there
are good reasons for surprising that
smell is highly developed in some of
them.
Sounds seem to affect them but little;
but OF this we are by no means certain,
for they may possess hearing organs at
tuned to perceive tones which make no
impression upon our comparatively dull
ears. As many of them produce sounds.
1t is probable that their fellows of the
same species can perceive them Ants
evidently do not hear sounds produced
by us, but it is the opinion of some that
they produce sounds among themselves
which are used to convey intelligence
from one to another. In certain birds,
especially those which fly by night, like
the owl. hearing is developed to a de
gree far beyond our own.
1t is very probable that fishes have to
rely to a great extent upon the sense of
smell; by it they are enabled to detect
food or enemies at immense distances.
In the shark the expanse of membrane
over which the examinations of the nerves
If smell are expanded is calculated TO be
twelve or thirteen square feet. This is
undoubtedly the most intelligent. as it is
the largest Of the true fishes. This sense
bears the SAINT relation to the intelli-
gence of the fish as is borne by the sense
of sight in the bird tribe. In these lat
ter, the sense of smell is very nper-
fectly developed, subordinated to that of
sight.
In many wild and domesticated quad
fhBTInf Ait ''liFF IL NCll ldlktiN utNtl-
oped. The American buffalo Tor bison,
and all the species of deer rely upon ii to
give them notice of approaching dan
ger. In the dog it is wonderfully acute;
in fact, in some species it seems TO con
fer powers upon the animal of which
the human beings can have but
the remotest comprehension 1t
seems probable that every object
has a distinct odor to the dog.
In fact. it seems 10 be for that
animal as important as that of vision, if
not more essential to his we'll being.
There are some very remarkable incl
dents recorded of a dog not only dis.
tinguishing individuals, but even voca-
tons by means of this sense. the camel
can detect water at least n mile away by
smell and frogs seem to possess the faculty
to a similar if not greater degree. The
horse, as is well known, makes great use
of this sense, and blind animals of this
species develop it to a high degree.
The sense of touch is not highly devel-
oped in fl hes or reptiles, but the carniv-
erous birds seem to be rather highly en-
lowed in this regard. In the higher ami
mails. especially the elephant, this sense
is sometimes found to be extremely
acute. In those animals which possess
claws ii is also much better developed
than in others. Rats are very sensitive,
and are able 70 avoid obstacles in their
rapid flight even after being blinded
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