Evening star. [volume] (Washington, D.C.) 1854-1972, 1858-08-30
WHAT Is BLOOD?

! Thousands Of our readers. doubtless, have
seen person bIed. They have probably OBJ
served, afterwards, that II divides into thin.
watery fuid, and athick clot, process which is
called coagulstion. They have been told that
though the abstraction Of few ounces Is not
very injurious nay, is by many considered
useful in cases of fevers, the loss of any eons;d
erable portion Is followed by death But here
their observations, perhaps their curiosity, have
ceased.
Yet there are many who may have often won.
dered what this blood can be, which is so ne
cessary to existence. What are its constituents
In what was is 1t 80 indispensable to life? How
muchis there in ahuman body? Is there much
waste, and if so, how is the waste repaired? Is
the blood all alike? Is the blood of horse, dog,
or other mere animals, similar to that of man
we shall answer these questions in order, be-
ginning with the last. - -
The blood Of n human being is essentially
different from that ofany other animal and the
blood Of one animal differs from that of another
The blood of horse is poison in dogs yeins,
The blood Of sheep, transferred into cat,
Kills the cat. The blood of any animal, except
one OF its own species, forced into the veins of
man, brings on paralysis and death. Science
has analyzed wherein the blood of one animal
varies from that of another and has shown that
what experiment has revealed, can also be de-
monstrated physiologicslly. ..H FI
Even in the same animal there are two kinds
of bloOds, one called arterial, which rushes from
the heart, and the other venous, which pours
into the heart. The first is bright scarlet, the
last purple. The first passes into smaller and
smaller vessels, till it reaches some under the
skin, q thousand times finer than the finest
needles point; the last flows from small into
larger channels, till it empties itself, in huge
Stream, into the heart. The arterial blood is
pare; the venous full of wasted tissues. The
Office of the lungs is to cleanse the venous
blood, which is then thrown back into the heart,
and afterwards propelled throughout the body
Tdus, ut will be seen, a continual waste and re-
pair goes on in the human body, of which waste
aud repair the blood is the instrument. 1t has
been estimated that, in the course of year. the
arteries carry to the various tissues not less
than three thousand pounds weight of nutritive
matter, while the veins brings back to the heart
and lungs, to be expired from the latter, as
many thousand pounds weight of wasted tiss ues
Both arterial and veuous blood contains oxygen
and carbonic gas, the popular notion TO the con-
trary notwithstanding but arterial blood con-
talns much the larger proportion of oxygen
In their constituents, the gases excepted their
Is but little difference between arterial and
venOuS blood.
In man OF average weight, the quantity of
blood is about ten pounds. How much of this
can be extracted, without causing loss Of life, it
Is difficult always to tell. In the medical book
there is statement of hysterical woman, who
was bled one thousand and twenty times in
nineteen years. A young man, according to
Haller, was bled seven pounds and a half daily
Tor ten days, and yet survived-a story almost
incred BILE The chief constituent of blood is
water, which forms nearly one-eighth of the
whole Albumen enters into its composition
In the proportion of seventy parts to q thousand
Sugar, salts, fat and cell matter compose the
remainder, the last in the proportion of one
hundred and thirty parts to a thousand.
These cells, or discs as others call them, are
the most curious part Of the blood. 1t would
be idle to enter into an explanation of their
composition, as scientific men themselves are not
creed upon the subject. Nor is it possible, in
the present stage Of human knowledge, to tell
how blood sustaius life, except as an instrument
and vehicle to carry on the repairs, and remove
the waste, which are indispensable to existence