Cattle 1853 - Lewis Family Farm

222 CATTLE.
numerous and large, and blood in large quantities pours on toward
the right auricle and ventricle of the heart. These 'tendinous cords,
and the muscular columns beneath, are very large and strong, in
order to afford adequate resistance to the greater pressure of the
blood. In this ventricle, there is also a band or fleshy muscle, running
across from one side to the other, the double effect of which is
beautifully evident, viz., to prevent this cavity from being too much
dilated, or possibly ruptured, when the blood flows rapidly into the
heart ; and to assist the ventricle in contracting on the blood. A smaller
and more tendinous band runs across the same ventricle, lower
down, and for the same purpose. From the peculiar arrangement of
the circulatory system, there is always this pouring on of blood to be
arterialized ; for the secretion of milk, or the deposition of fat, con-
stitute the daily, unremitting duties of the animal. There is given,
not only to provide against accident, but to fit the heart for this
incessant hard work, this supplemental muscle, in the form of a fleshy
band stretching across from one side to the other, preventing dilata-
tion and assisting in contraction.
The blood is driven out of the right ventricle into the lungs, and is
there exposed to the action of the atmospheric «ir, and purified
thence it is returned to the left auricle, passes into the left ventricle,
and, by the contraction of that cavity, is propelled through the arteries.
The aortas are the large vessels which first receive the blood from
the heart in order to carry it through the body. The vessels from
the left ventricle, which carry the arterial blood through the frame,
and those from the right ventricle, that convey the venous blood to
the lungs, alike spring from the muscular and fleshy septum, or wall,
that separates the cavities of the heart, and divides that organ into
two distinct parts. The ventricles of the heart of the ox have constant
and hard work to do, and additional strength is given by the
insertion of a bone into the septum at the base of these arteries, more
belonging to the aorta than to the pulmonary artery, but meant as a
support to both.
The heart is subject to inflammation. It is principally recognized
by the strength of the pulse, and by the bounding action of the heart,
evident enough when the hand is placed on the side of the chest, and
which may be seen and heard even at a distance.
THE ARTERIAL SYSTEM.
The blood is carried on through the arteries by the force of the
heart. These are composed or three coats ; the outer, or elastic, by
which they yield to the gush of blood ; the- muscular coat, by which
the artery contracts again when the gush of blood has passed ; and
the inner, or smooth, glistening coat, which lessens the friction of the
blood against the side of the vessel, and its consequent gradual retar-
dation in its course.
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