Below the level of the backbone, after the haunch-bone, comes
the hip-socket; then the leg-bones, those in the thighs and those in
the shins, which are termed colenes or limb-bones, a part of which
is the ankle, while a part of the same is the so-called 'plectrum'
in those creatures that have an ankle; and connected with these
bones are the bones in the feet.

On the upper part of the course of the backbone are the
collar-bones and the ribs. The chest rests on ribs; and these ribs
meet together, whereas the others do not; for no animal has bone in
the region of the stomach. Then come the shoulder-bones, or
blade-bones, and the arm-bones connected with these, and the bones
in the hands connected with the bones of the arms. With animals that
have forelegs, the osseous system of the foreleg resembles that of the
arm in man.

The skull is not formed alike in all animals. In some animals
the skull consists of one single undivided bone, as in the case of the
dog; in others it is composite in structure, as in man; and in the
human species the suture is circular in the female, while in the
male it is made up of three separate sutures, uniting above in
three-corner fashion; and instances have been known of a man's skull
being devoid of suture altogether. The skull is composed not of four
bones, but of six; two of these are in the region of the ears, small
in comparison with the other four. From the skull extend the jaws,
constituted of bone. (Animals in general move the lower jaw; the river
crocodile is the only animal that moves the upper one.) In the jaws is
the tooth-system; and the teeth are constituted of bone, and are
half-way perforated; and the bone in question is the only kind of bone
which it is found impossible to grave with a graving tool.

The bones in animals are all connected with one single bone, and
are interconnected, like the veins, in one unbroken sequence; and
there is no instance of a bone standing apart by itself. In all
animals furnished with bones, the spine or backbone is the point of
origin for the entire osseous system. The spine is composed of
vertebrae, and it extends from the head down to the loins. The
vertebrae are all perforated, and, above, the bony portion of the head
is connected with the topmost vertebrae, and is designated the
'skull'. And the serrated lines on the skull are termed 'sutures'.

For instance, we fail

to find it in the blood of the deer, the roe, the antelope, and some
other animals; and, owing to this deficiency of the fibrous tissue,
the blood of these animals does not coagulate to the extent observed
in the blood of other animals. The blood of the deer coagulates to
about the same extent as that of the hare: that is to the blood in
either case coagulates, but not into a stiff or jelly-like
substance, like the blood of ordinary animals, but only into a flaccid
consistency like that of milk which is not subjected to the action
of rennet. The blood of the antelope admits of a firmer consistency in
coagulation; for in this respect it resembles, or only comes a
little short of, the blood of sheep. Such are the properties of
vein, sinew, and fibrous tissue.

The ines (or fibrous connective tissue) are a something
intermediate between sinew and vein. Some of them are supplied with
fluid, the lymph; and they pass from sinew to vein and from vein to
sinew. There is another kind of ines or fibre that is found in
blood, but not in the blood of all animals alike. If this fibre be
left in the blood, the blood will coagulate; if it be removed or
extracted, the blood is found to be incapable of coagulation. While,
however, this fibrous matter is found in the blood of the great
majority of animals, it is not found in all.

There is a very extensive system of sinews connected severally
with the feet, the hands, the ribs, the shoulder-blades, the neck, and
the arms.

All animals supplied with blood are furnished with sinews; but
in the case of animals that have no flexures to their limbs, but
are, in fact, destitute of either feet or hands, the sinews are fine
and inconspicuous; and so, as might have been anticipated, the
sinews in the fish are chiefly discernible in connexion with the fin.

Sinew is fissile lengthwise, but crosswise it is not easily
broken, but admits of a considerable amount of hard tension. In
connexion with sinews a liquid mucus is developed, white and
glutinous, and the organ, in fact, is sustained by it and appears to
be substantially composed of it. Now, vein may be submitted to the
actual cautery, but sinew, when submitted to such action, shrivels
up altogether; and, if sinews be cut asunder, the severed parts will
not again cohere. A feeling of numbness is incidental only to parts of
the frame where sinew is situated.

In the ham, or the part of the frame brought into full play in the
effort of leaping, is an important system of sinews; and another
sinew, a double one, is that called 'the tendon', and others are those
brought into play when a great effort of physical strength is
required; that is to say, the epitonos or back-stay and the
shoulder-sinews. Other sinews, devoid of specific designation, are
situated in the region of the flexures of the bones; for all the bones
that are attached to one another are bound together by sinews, and a
great quantity of sinews are placed in the neighbourhood of all the
bones. Only, by the way, in the head there is no sinew; but the head
is held together by the sutures of the bones.

For the veins have the shape of the entire body, like a sketch
of a mannikin; in such a way that the whole frame seems to be filled
up with little veins in attenuated subjects-for the space occupied
by flesh in fat individuals is filled with little veins in thin
ones-whereas the sinews are distributed about the joints and the
flexures of the bones. Now, if the sinews were derived in unbroken
sequence from a common point of departure, this continuity would be
discernible in attenuated specimens.

The sinews

of animals have the following properties. For these
also the point of origin is the heart; for the heart has sinews within
itself in the largest of its three chambers, and the aorta is a
sinew-like vein; in fact, at its extremity it is actually a sinew, for
it is there no longer hollow, and is stretched like the sinews where
they terminate at the jointings of the bones. Be it remembered,
however, that the sinews do not proceed in unbroken sequence from
one point of origin, as do the blood-vessels.

In all sanguineous animals the case stands as here set forth in
regard to the points of departure and the courses of the chief
veins. But the description does not hold equally good for the entire
vein-system in all these animals. For, in point of fact, the organs
are not identically situated in them all; and, what is more, some
animals are furnished with organs of which other animals are
destitute. At the same time, while the description so far holds
good, the proof of its accuracy is not equally easy in all cases,
but is easiest in the case of animals of considerable magnitude and
supplied abundantly with blood. For in little animals and those
scantily supplied with blood, either from natural and inherent
causes or from a prevalence of fat in the body, thorough accuracy in
investigation is not equally attainable; for in the latter of these
creatures the passages get clogged, like water-channels choked with
slush; and the others have a few minute fibres to serve instead of
veins. But in all cases the big vein is plainly discernible, even in
creatures of insignificant size.

Furthermore, from the aorta and the great vein at the points of
divarication there branch off other veins. Some of these run to the
groins-large hollow veins-and then pass on down through the legs and
terminate in the feet and toes. And, again, another set run through
the groins and the thighs cross-garter fashion, from right to left and
from left to right, and unite in the hams with the other veins.

In the above description we have thrown light upon the course of
the veins and their points of departure.

There is no vessel that runs from the aorta into the liver or
the spleen.

From each of the two great blood-vessels there extend branches
to each of the two flanks, and both branches fasten on to the bone.
Vessels also extend to the kidneys from the big vein and the aorta;
only that they do not open into the cavity of the organ, but their
ramifications penetrate into its substance. From the aorta run two
other ducts to the bladder, firm and continuous; and there are other
ducts from the hollow of the kidneys, in no way communicating with the
big vein. From the centre of each of the two kidneys springs a
hollow sinewy vein, running along the backbone right through the
loins; by and by each of the two veins first disappears in its own
flank, and soon afterwards reappears stretching in the direction of
the flank. The extremities of these attach to the bladder, and also in
the male to the penis and in the female to the womb. From the big vein
no vein extends to the womb, but the organ is connected with the aorta
by veins numerous and closely packed.

As far as the kidneys, each of the two remaining undivided, the
aorta and the big vein extend; and here they get more closely attached
to the backbone, and branch off, each of the two, into a A shape,
and the big vein gets to the rear of the aorta. But the chief
attachment of the aorta to the backbone takes place in the region of
the heart; and the attachment is effected by means of minute and
sinewy vessels. The aorta, just as it draws off from the heart, is a
tube of considerable volume, but, as it advances in its course, it
gets narrower and more sinewy. And from the aorta there extend veins
to the mesentery just like the veins that extend thither from the
big vein, only that the branches in the case of the aorta are
considerably less in magnitude; they are, indeed, narrow and
fibrillar, and they end in delicate hollow fibre-like veinlets.

And in like manner

the parts of the lesser one of the two chief
blood-vessels, designated the aorta, branch off, accompanying the
branches from the big vein; only that, in regard to the aorta, the
passages are less in size, and the branches very considerably less
than are those of the great vein. So much for the veins as observed in
the regions above the heart.

The part of the great vein that lies underneath the heart
extends, freely suspended, right through the midriff, and is united
both to the aorta and the backbone by slack membranous communications.
From it one vein, short and wide, extends through the liver, and
from it a number of minute veins branch off into the liver and
disappear. From the vein that passes through the liver two branches
separate off, of which one terminates in the diaphragm or so-called
midriff, and the other runs up again through the armpit into the right
arm and unites with the other veins at the inside of the bend of the
arm; and it is in consequence of this local connexion that, when the
surgeon opens this vein in the forearm, the patient is relieved of
certain pains in the liver; and from the left-hand side of it there
extends a short but thick vein to the spleen and the little veins
branching off it disappear in that organ. Another part branches off
from the left-hand side of the great vein, and ascends, by a course
similar to the course recently described, into the left arm; only that
the ascending vein in the one case is the vein that traverses the
liver, while in this case it is distinct from the vein that runs
into the spleen. Again, other veins branch off from the big vein;
one to the omentum, and another to the pancreas, from which vein run a
number of veins through the mesentery. All these veins coalesce in a
single large vein, along the entire gut and stomach to the oesophagus;
about these parts there is a great ramification of branch veins.

Hence again they branch off

into four veins, of which one bends back and descends through the
neck and the shoulder, and meets the previous branching off of the
vein at the bend of the arm, while the rest of it terminates at the
hand and fingers. (See diagram.)

Each vein of the other pair stretches from the region of the ear
to the brain, and branches off in a number of fine and delicate
veins into the so-called meninx, or membrane, which surrounds the
brain. The brain itself in all animals is destitute of blood, and no
vein, great or small, holds its course therein. But of the remaining
veins that branch off from the last mentioned vein some envelop the
head, others close their courses in the organs of sense and at the
roots of the teeth in veins exceedingly fine and minute.

But up above all these,

from that part which is connected with the
heart, the entire vein branches off in two directions. For its
branches extend to the sides and to the collarbones, and then pass on,
in men through the armpits to the arms, in quadrupeds to the forelegs,
in birds to the wings, and in fishes to the upper or pectoral fins.
(See diagram.) The trunks of these veins, where they first branch
off, are called the 'jugular' veins; and, where they branch off to
the neck the great vein run alongside the windpipe; and,
occasionally, if these veins are pressed externally, men, though not
actually choked, become insensible, shut their eyes, and fall flat on
the ground. Extending in the way described and keeping the windpipe
in betwixt them, they pass on until they reach the ears at the
junction of the lower jaw with the skull.

The branches

of the blood-vessels lie above the tubes that
extend from the windpipe. And that vessel which extends to the
vertebra of the neck and the backbone, stretches back again along
the backbone; as Homer represents in the lines:-

(Antilochus, as Thoon turned him round),

Transpierc'd his back with a dishonest wound;

The hollow vein that to the neck extends,

Along the chine, the eager javelin rends.

From this vessel there extend small blood-vessels at each rib
and each vertebra; and at the vertebra above the kidneys the vessel
bifurcates. And in the above way the parts branch off from the great
blood-vessel.

First of all

, then, upwards from the heart there stretches a
part of the great blood-vessel towards the lung and the attachment
of the aorta, a part consisting of a large undivided vessel. But there
split off from it two parts; one towards the lung and the other
towards the backbone and the last vertebra of the neck.

The vessel, then, that extends to the lung, as the lung itself
is duplicate, divides at first into two; and then extends along by
every pipe and every perforation, greater along the greater ones,
lesser along the less, so continuously that it is impossible to
discern a single part wherein there is not perforation and vein; for
the extremities are indistinguishable from their minuteness, and in
point of fact the whole lung appears to be filled with blood.