Such an outline represents the form and position of the stomach when distended; but it is to be understood that its dimensions depend upon the amount of its contents. It is capable of holding about 7 pints. The junction of œsophagus and stomach is closed by a muscular ring, or sphincter muscle—the cardiac sphincter; the junction of stomach and intestine is guarded by a much stronger pyloric sphincter. The average diameter of the small intestine is about 1½ inches. It is wide enough, therefore, to admit two fingers. The length of the tube is about 22 feet. Its first part is termed the “duodenum,” because its length equals the breadth of twelve fingers—_i.e._, about 9 inches. The remainder is divided arbitrarily into jejunum and ileum. The duodenum makes three sharp curves. First it inclines upwards and to the right, then vertically downwards, then horizontally to the left, and finally forwards. The ducts of the liver and pancreas open by a common orifice into the descending portion. Its horizontal portion is bound firmly to the vertebral column. After this the whole of the small intestine is supported by the mesentery, a double fold of peritoneum which allows it to hang freely in the abdominal cavity. The mesentery is attached to the back of the body-wall. Commencing on the left side of the second lumbar vertebra, its line of attachment inclines obliquely downwards and to the right, across the vertebral column, for about 6 inches. Measured from its attached edge to the edge which bears the intestine, it has a width of about 8 inches. Its free border has, as already said, a length of 22 feet. Its measurements being as just stated, it is clear that it must be folded backwards and forwards upon itself, like a goffered frill. In the right groin the small intestine joins the large intestine, or colon. It does not, as might have been expected, simply dilate into the large intestine, but enters it on its mesial side, its orifice being guarded by the ileo-colic valve. In other words, the large intestine projects downwards beyond this orifice, as the cæcum coli. In many animals the cæcum is of great length and capacity. In the human embryo it begins to assume a similar form; but a very small portion only (the so-called “cæcum” of human anatomy) dilates to the calibre of the colon. The real cæcum retains throughout life its embryonic calibre. It has a length of about 3½ inches, and a diameter of not more than ¼ inch. This is the “vermiform appendix,” of ill fame, which must be looked upon as one of Nature’s misfits. Its great liability to become inflamed is commonly explained as due to the tendency of such articles of food as pips, the fibre of ginger, flakes from the inside of enamelled saucepans, etc., to become lodged in its cavity. But whether this explanation be correct or no—and there are reasons for thinking it somewhat fanciful—it is much to be wished that the process of evolution would hasten the disappearance of this