The Cambria freeman. [volume] (Ebensburg, Pa.) 1867-1938, 1889-08-09
THE BATRACHIA.
Points About the CIammy BIusi-
clans of the Marshes.
They Have Played an Important Part In
the Developments or Physiological
Science Their Many PecuIiari-
tIss-EarIoUs Species,

II IS true that the frog is n common
and rather despised animal. At
casual acquaintance there is nothing
attractive about him, either IL appear
CLce OF behavior.
But while the frog at first acquaint-
aUce Seems in nowise q noteworthy
animal, it is stiu true that no living
creature of tho fields aud ST teams Is
in as many ways SO interesting. 1t IS
q classic animal in the field Of expert
mental physiology. II was in the web
of the frogs foot that that fact OF
fundamental interest in the medical
treatment of diSease-the circulation
% the bIood-was first definitely OBJ
served And it was the accidental OBJ
servutiou Of Calvin, made in 1890,
that pair Of frogs legs, suspended
on a copper hook and in contact with
a plate OF iron below, were
thrown into violent coutractions, that
led 10 the discovery Of GaIvauic (nOw
ehcmicaD electricity. Endless eNper-
imel;s have been made upon the It's
sues and organs Of the frog, all throw
ing light upon the physiological action
Of the corresponding parts in the hui
man body. For example, the muscles
Ot frogs leg may be so dissccted rs
20 expose the nerve connected with
them; II the nerve be then stimulated
by a current Of electricity or even by
piuChiug. the muscles Will contract.
In this way much has been learned
about the physiology Of these tissues.
The reason why the frog IS especially
available for the purposes Of physio-
logical experiments is that its tissues
are exceedingly tenacious OF life.
Under suitable conditions the muscle
and nerve preparations just referred
20 viii respond to stimulation several
hours after the life Of the animal has
been taken. The remarkable power
ui retaining vitality is still better seen
I'm the action Of tho heart, since this
organ viii go on beating for two days
after life has ceased in the animal.
This same tenacity Of life is true OF
some other reptilian and other low
animals, as birds and mammals
The frog, then, having so well estab-
lshcd n claim on our interest, is de-
serving OF some notice in respect TO
It's specific characters rs IN animal
The place which IL occupies in the
scale Of animal life is intermediate be-
tween that OF the fishes and the rep
tiles This is indicated very clearly in
The history of its individual devel-
opment. 1t Is well known that in
what may be called the period OF
youth I'm the frog the form Of the BODY
and the manner Of life are quite differ
ent from the same in the fuII-grown
animal. Now in the early part of this
tadpCle period the creature has all OF
the essential characteristics Of a fish.
It's body Is elongated and terminates in
broad fat tail There are no legs and
it breatLes by means Of gills. At this
time, too, IL lives on plant food. crop
ping the leaves Of water plants by
means Of horny plates with which
its jaws are provided. But when
the tadpole stage is passed and
the frog nature fully acquired,
The animal then possesses all the
distinctive characteristics Of q reptile.
lt has two pairs Of limbs, 4 scaleIess
skin, and broathes by means Of lungs.
OF these changes the most striking is
-hat from a water-breather Cair dis
"'.f - Al "AtEAl ~ al sl4E-DrtSiIler.
II is for this reason that the frog, to-
gether with other animals possessing
the same pecUliarity, is placed in the
geological class Amphibia, the word
meaning doubIe-life. Some natural
lists, however, prefer the name Ba-
trachia, the original meaning of this
word being frog.
The length Of time required for the
development OF the frog appears to
depend closely upon temperature ana
other external conditions. The writer
placed a tadpole in an aquarium in
the fall and no growth whatever ap-
peared 70 take place until the follow
ing spring. But when growth was
once renewed it proceeded with great
rapidIty. Within a period OF ten days
both pairs Of legs budded ont and de-
veioped 10 nearly perfect form. The