Organs of the Animal Body : tlicir Forms and Uses. 31 
■interesting thing about the fleshy structure, its peculiar power 
of contracting. The contraction or shortening of the muscles 
may be seen during the cutting up of the carcass, if the animal 
has just been killed ; indeed it cannot escape notice, because every 
time the muscle is touched it jerks and moves quickly and with 
some force, so as to give rise to the idea, and cause often the ex- 
pression of it in words, that the structure is alive, which is quite 
true, although the animal of which it forms a part is dead. 
Muscle (flesh) is the structure by which all the motions of 
the animal body are carried on. Some of the actions are due 
to the animal's will ; but many very necessary things are done 
by the muscles themselves, directed by the nerves, without the 
animal knowing anything about the matter. The circulation 
of the blood, breathing, the motions going on in the intestines 
— the muscles of which are white instead of red — are all done 
without any effort of the animal, and some of them without its 
knowledge. 
Breathing Organs. — Having observed the muscle, fat, and 
white fibre on the surface of the skinned carcass, the operator 
should next remove the fore-limb on the side most convenient to 
him by cutting through the flesh (muscles) which joins the 
shoulder to the trunk. Next, he should cut through the flesh or 
muscles at the upper part of the trunk, about six inches or a foot 
from the centre of the back, according to the size of the animal, 
all along the ribs to the flank, and with his saw cut through 
the ribs along the same line. A second cut with the saw along 
the lower portion of the ribs, where they join the breast-bone 
(sternum), will enable him to carry his knife along the lower 
part of the ribs, right up to the line at the top of the trunk 
which he began with, and thus to expose the whole of the 
cavity of the chest, leaving the abdominal cavity still closed. 
By the removal of the wall of the chest the operator has 
exposed the chief breathing organs — the lungs ; and by cutting 
through the windpipe and some large vessels, and also through 
the connection between the sac which invests the heart and 
the breast-bone, the lungs, heart, and large vessels can be lifted 
out of the chest for nearer inspection. 
In Fig. 19, p. 32, the lungs and heart of a sheep are shown as 
they appear when taken from the chest in the manner described. 
To be perfectly healthy the lungs should be smooth on the out- 
side, of a clear pink colour ; they should yield easily to pressure, 
and to the touch should give the idea of being filled with air. 
Not resting satisfied with the outside appearance, the ob- 
server should cut open the piece of windpipe which is attached 
to the lungs, and continue the cutting along the divisions of the 
tubes as they extend into the substance of the lungs. It will not 
