7. Extending in this manner, and receiving the trachea between them, they reach the place where the jaws unite with the head; and again from this point they are divided into four veins, one of which bends backwards and descends through the neck and shoulder, and meets the first division of the vein by the joint of the arm; the other portion terminates in the hand and fingers; and another branch extends from each part near the ear to the brain, where it is divided into many small branches upon the membrane which surrounds the brain. 8. The brain never contains blood in any animal, nor does any vein, small or great, terminate upon it; but some of the other branches that extend from this vein surround the brain in a circle, and others, end upon the organs of sense and the teeth in very small veins. In the same manner, also, the branches of the smaller vein, which is called the aorta, are divided: they are continued beside those of the great vein, but the tubes are smaller and the branches less than those of the great vein. CHAPTER IV. 1. The veins, then, are thus distributed in the parts above the heart, but the part of the great vein which is below the heart passes through the middle of the diaphragm, and is united to the aorta and spinal column by membranous flaccid passages. From this a short and wide vein passes through the liver, from which many similar branches extend to the liver, and disappear upon it. There are two branches of the vein, one of which terminates upon the diaphragm, and what is called the præcordia, the other returns through the arm-pit to the right arm, and unites with the other veins near the interior part of the elbow. For this reason physicians treat certain diseases of the liver by venesection in this vein. 2. From the left of this there is a short and wide vein, which reaches to the spleen, and the branches of this vein are lost upon this organ, and another portion branching off in the same way from the left the great vein passes up to the left arm, except that the last-mentioned pass through the liver, but this one through the spleen. Other branches also separate from the great vein, the one to the omentum, the other to the pancreas; and from this many veins extend through the mesenterium, and all end there in one great vein, which passes through the whole intestine and the stomach, as far as the œsophagus; and many veins branch off from them around these parts. 3. Both the aorta and the great vein continue as far as the kidney each as a single duct; from this point they are more closely united to the spinal column, and are each divided into two parts, like the letter lambda (Λ), and the great vein is placed farther back than the aorta. The aorta is more closely united to the spinal column, near the heart, and the junction is formed by small sinewy veins.