Vermont watchman and State journal. [volume] (Montpelier, Vt.) 1836-1883, 1855-07-20

ration as the existence Of few holes
on the back side Of the lungs in birds,
makes all the difference. These orr
fees allow the air to pass into the cav
ity Of the abdomen, and even into the
very bones Of birds of fight The
natural elasticity Of their long prens,
bone draws the air into these cavities
through their small dense lungs and
muscular effort forces it out. In this
way the air is acted on toice by the
lungs, as coal in the nose Of bel
lows would be famed by both the
currents ingrcsS and that Of egress.
In this way also is secured a great
extension Of lung surface, FOR all the
cavities Of the body in these birds act
more or less us lungs, and at the same
time that extension of outside surface
is attained that is necessary 10 effect
movements in so thin fluid as the
atmosphere, while the whole weight
Of matter in the bird is disposed of
in such a way as to be strongest, like
a sheet Of paper made into roll.
This extension Of surface and hallow
arrangement Of homes is wanting in
those birds that do not fly so that
when Cuvier found BIRDS bone pos
sessing such IN internal structure as
the bones Of quadrupeds do, judging
from this fact he fearlessly asserted
that it belonged TO bird more aoing-
less than even the ostrich, and the
subsequent discovery OF complete
fossil skeleton proved that it did not
possess even The APPENDICES Of
wings.
And here the doctor, drawing to
him the piece Of bark and the rem
nant OF frog from where had laid
them before dinner, carefully delach-
ed the lungs with his pen-knl(c and
inflated them with Il straw as boys
blow up soap bubbles with pipe-slem.
Having secured the air within by
placing a thread around the trachea,
he continued
Lungs whether intended ulli-
mately for the use of frogs, or birds,
or men, start in the same way, like a
bud, from the back part Of the diges-
tive tube in some portion Of lis length.
In all other animals except birds this
one cavity remains closed at its lower
extremity, being a mere sack. In
birds, however, il communicates with
the abdomen, and this difference,
trIllIng as Il may appear, gives entire
ly different and very superior powers
TO their breathing apparatus. And
yet as their geologic period is coesal
with reptiles, SO their lungs are the
mcmbranous lungs of reptiles unex-
banded, and like them allow the air
to &C; upon the contained blood from
only one side. There is in all lungs
thin membrane that lines them
/ throughout, and through which air
may pass readily in each direction
while the blood is retained. The
heshy and spongy lungs Of mammal
las allow the air 10 act through this
skin on The blood from both sides. In
all kinds of lungs the air is allowed
to act on the blood only through this
SraiHci, and it is only when it is torn
that bleeding at the lungs occurs.
From the double nature of the heart
in men and the higher animals, it re-
suits that the two sides of IT, though
they do not intcrcommunicate, must
yet throb together, SO that an equal
amount of blood must be sent 10 the
muscles on one side Of 1t and TO the
lungs on the other AT each pulsaiion.
When horses are oyer-driyen, as they
are in racing, the muscles may de-
mand more blood and faster than il
can pass through the lungs, and I'M
der this pressure the thin Inning mem
brane is burst in places aud the horse
pants a bloody foam. So too, a deep
and WIDE chest in an animal indicates
powerful muscles.
Is it, said !, because birds are
all chest made so like a bellows
that they have such powers Of voice ?
Not altogether, for they have Pc
cullar vocal apparatus at the bottom
Of their wind-pipc. On opening the
bill of a dead crow and compress
ing his abdomen you may make him
car most admirably; showing that
voice depends after oil on purely me-
chanical causes. The bird, take him
altogether, mouth, wind-pipe, vocal
organs, legs, and body-might oe
represented by a clarlonet with bel
lows for an attachment. The vocal
power conferred 10y this arrangement
is wonderful. IT the voice ., 49, =,
coould be heard as far in proportion
10 his size, one might sit with his feet
on the fender by his own fire and lis
ten 10 congressional debates or legis-
latiye proceedings or Sunday sermons,
If indeed the jargon did not rem
der all sounds uninielligible.
Il am glad said, that our leg
islators have not been endowed with
any such ultra-stentorian powers
But to return TO our subject con-
tinued my anatomical friend, and with
this ancient pun, he divided the YER