The inferior vena cava, like the aorta, divides into two great branches, the iliac veins, _u_, the sub-divisions of which accompany those of the arteries, and are called by the same names. The manner in which the superficial veins ramify and anastomose with each other is shown on the upper and lower extremity of the left side. ORGANS OF DIGESTION. FIGURE 1.—_General View of the Digestive Organs of Man_.—This figure is intended to give a general idea of the forms and relative positions of the organs of digestion.—_a_, The œsophagus. _b_, The stomach. _c_, The duodenum, _d_, _d_, _d_, Convolutions of the small intestine. _e_, The cœcum. _f_, Appendix of the cœcum. _g_, Opening of the small into the large intestine. _h_, The ascending colon. _i, i_, Transverse arch of the colon. _j_, The descending colon. _k_, The liver. _l_, The gall-bladder. _m_, The pancreas, mostly covered by the stomach. _o_, The spleen.—In this figure, the liver is raised up and the transverse arch of the colon drawn down, in order to show parts which they cover when in their natural situation. [Illustration: Fig. 1] FIGURE 2.—_General Aspect of the Abdominal Viscera_.—In this figure, the anterior walls of the abdomen are removed, so as to show the organs in their natural positions. The small intestine is removed.—_a_, The liver, situated beneath the right arch of the diaphragm. _b_, The stomach. _c_, Epiploa, or floating folds of the peritoneum. _d_, Summit of the gall-bladder. _e_, _e_, Large intestine, showing all its courses. [Illustration: Fig. 2] ORGANS OF CIRCULATION.—HEART AND LUNGS. FIGURE 1.—_Front View of Heart and Lungs_.—Both organs are stripped of their envelopes, the pleura and pericardium. The right lung is drawn aside, so as to uncover the heart and large vessels. The left lung is deeply dissected, to show the distribution and mode of ramification of the air-tubes and blood-vessels. [Illustration: Fig. 1] _a_, The larynx. _b_, The trachea.—The right lung is somewhat shorter than the left, and is divided into three lobes, _c_, _d_, _e_; while the left lung has but two lobes, _f_, _g_. The surface of the lobes is sub-divided into lobules, by the intersection of great numbers of depressed lines. _h_, Right auricle of the heart. _i_, Right ventricle. _j_, Left auricle. _k_, Left ventricle. _l_, The aorta. _m_, The pulmonary artery. _n_, Left pulmonary veins.—These veins are four in number, two for each lung; and they return to the heart the blood which has been conveyed into the lungs by the pulmonary artery. The division of the pulmonary artery into right and left branches cannot be seen in this figure, being hidden by the aorta. _o_, The superior vena cava. _p_, Root of the right innominate artery, springing from the arch of the aorta. _q_, Root of the left sub-clavian artery. _r_, Root of the left carotid artery. [Illustration: Fig. 2]