

DISSECTION OF AN ANIMAL. 37 



called mesenteries. A large apron-like fold of the peritonaeum, con- 

 taining much fat, and named the great omentnm, also hangs down from 

 the stomach and transverse colon, over the small intestines, and 

 doubtless serves to protect them and preserve their temperature : it is 

 not shown in any of our figures. The peritonaeum is also reflected on 

 to the spleen and likewise from the diaphragm over a great part of 

 the liver, assisting to support it and to form its so-called ligaments ; 

 but the pancreas, and the kidneys and supra-renal bodies are alto- 

 gether behind it. 



DISSECTION OF AN ANIMAL. 



There are many respects in which the preceding outline of the general plan 

 of construction of the human body will be better understood, if the student at 

 this stage procure and dissect the body of a dog or rabbit. The latter being 

 more easily obtained is described here. Due allowance must of course be 

 made for differences, not only in the size, but also in the form, color, and 

 strength of construction of the parts of the animal as compared with the 

 human organs. The student will find the following course of dissection the 

 most convenient and useful : 



Place the dead animal on its back, secure the legs, and then divide the skin 

 only along a line reaching from beneath the chin to the lower part of the 

 abdomen. In now reflecting the skin, by dissection, from the subjacent parts, 

 the loose subcutaneous areolar tissue, containing in its areolee or meshes more or 

 less fat or adipose tissue, will be met with, and cut across. When the skin is 

 reflected, say from off the right half of the body, the soft pinkish flesh will be 

 visible through the thin, firm, fibrous membrane called the fascia; which will 

 be found easier to display on the limbs than elsewhere. The fascia being now 

 removed by another step in the dissection (taking care that the knife be made 

 to follow the direction of the fleshy bundles which are being exposed), the flesh 

 itself, or muscular substance, is seen to be collected into masses, forming the 

 so-called muscles, and separated from one another by loose areolar tissue, or 

 by firmer membranes, called intermuscular septa. The muscles of the thigh 

 and leg will be found the easiest to dissect. Some muscles will be seen to have 

 direct and broad attachments to the skeleton, and others to be indirectly con- 

 nected to the bones by either broad, or long and slender, whitish, inextensible 

 cords called tendons. The latter are principally found in the limbs ; one of the 

 most remarkable being placed at the back of the leg, and connecting the mus- 

 cles of the calf with the heelbone. In dissecting the muscles on the inner side 

 of the thigh, the large bloodvessels proceeding out of the abdomen will be met 

 with, being known, the vein, by its being a flaccid tube containing blood, and 

 the artery by its remaining open or gaping, if cut across. Near these vessels, 

 some slender white cords, which are nerves, may be detected ; but the chief 

 nerve of the thigh will be found at the back of that part of the lower limb, de- 

 scending amongst the muscles into the ham, or space at the back of the knee. 

 Absorbent vessels also exist, but they are much too minute and delicate to be 

 detected except by the most expert anatomist using very special means of re- 

 search ; the absorbent glands will probably also be overlooked, in the fat and 

 cellular tissue of the groin. The muscles and their tendons being now cleanly 

 cut away from the side of the pelvis, and from the thigh and leg, the exposed 

 bones are seen to be whitish, moist, though hard structures, covered closely 

 with a tough membrane, the periosteum, portions of which may be dissected or 

 stripped off. The joints of the thigh and knee may now be cleaned externally; 

 and their ligaments, the fibrous bands which tie the respective bones together, 

 may be examined. On cutting through the latter, the closed sacs, or cavities 

 of the joints, will be opened, showing the articular ends of the bones, nicely 

 modelled so as to fit together, and covered with closely adherent and beauti- 

 fully smooth cartilage, the whole moistened with the viscid fluid, synovia, 

 secreted from a thin synovial membrane which covers the interior of the joint, 

 excepting the cartilages. After this, the thigh bone maybe cut or broken 



