SPLANCHNOLOGY. 197 



to take up any chyle that may have escaped those in the ileum, as also the 

 watery parts of the food, and the faeces become hardened by degrees, and 

 moulded or figured according to the length of time they are lodged in the 

 cells of the colon. The great length of this tube, as well as its yielding 

 structure, adapt it as a reservoir capable of retaining a considerable quan- 

 tity, and thus obviating the inconvenience of frequent defecation. The 

 rectum also contributes to the same effect, being retained in a closed state 

 by the sphincters and supported by the levatores ani muscles. When the 

 evacuation of the bowels is called for by the peculiar sensations in the part, 

 the contents are expelled partly by the muscular action of the rectum and 

 the concurring relaxation of its sphincter, aided by the voluntary contrac- 

 tion of the diaphragm and abdominal muscles. 



PI, lSO,ßg. 11, stomach with its fleshy fibres : '' ", longitudinal fibres from 

 the cardiac orifice ; ', circular and transverse fibres. Fig. 12, oesophagus at 

 its entrance into the stomach: ', mucous membrane of the oesophagus; 

 *, do. of the stomach ; ', line of separation between the two ; the inequali- 

 ties indicate the cardiac orifice. Fig. 13, valve of the pylorus. Fig. 14, 

 intestinal tract : ', coils of the small intestines ; ', coecum with its vermi- 

 cular appendage; % ascending, ■*, transverse, ', descending colon; ', sigmoid 

 flexure ; ', rectum ; % appendices epiploic«, folds of the peritonaeum filled 

 with fat. Fig. 15, portion of tlie small intestines opened to show the val- 

 vulae conniventes. Fig. 16, coecum opened : ', end of the ileum ; ''^ vermi- 

 cular appendage ; ', its opening into the coecum ; ', opening of the ileum ; 

 ''' ', folds of the mucous membranes, forming the lips of the valves. 



The glandular viscera of the abdomen which are subservient to digestion 

 and assimilation are, the liver, spleen, and pancreas. 



6. The Liver is the largest and heaviest secreting gland in the body ; it 

 is situated below the diaphragm, and above the right kidney, the stomach, 

 duodenum, and lesser omentum ; and is supported in this position by several 

 folds of the peritonaeum, inaccurately termed ligaments, viz. the falciform, 

 round, right, left, and coronary. These connect it to the diaphragm and to 

 the abdominal muscles, and the lesser omentum attaches it to the stomach 

 and omentum. Its weight varies from three to five pounds, depending on 

 the amount of blood included ; its transverse diameter is about ten or 

 twelve inches, the vertical about seven in the deepest part of the right lobe. 

 The liver is of very irregular form. The superior or anterior surface is 

 smooth and convex, and divided by the suspensory ligament into a right 

 and left portion. The inferior surface looks backwards and downwards ;. it 

 is very irregular, and marked by several projections and depressions. The 

 former are called lobes, and are five in number : first, the great or right 

 lobe ; secondly, the left lobe^ which rests on the stomach; third, the spigelian 

 or middle lobe^ situated behind the lesser omentum ; fourth, the lobulm 

 cnudatus, immediately behind the transverse fissure ; fifth, the lobulus qua- 

 dratus or anonyiuus, at the anterior part of the right lobe. 



The principal depressions or fissures on the inferior surface of the liver 

 are: the transverse fissure or porta., situated between the lobulus quadratus 

 and caudatus ; the horizontal fissure^ extending from the notch in the 



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