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evident towanls the insertion of the oesophagus into the stomach, and that 

 the muscular tuho is at this point so narrow, that it is almost exactly tilled 

 by the folds of mucous membrane it contains. For this reason it is that 

 wo may inflate a stomach hy the pylonis, without applying a ligature to 

 the oesophagus; the a port tiro of the canal being so perfectly closed that it 

 docs not allow a bubble of air to escape. In describing the interior of the 

 stomach, we will refer to the consequences resulting from this interesting 

 anatomical fact. 



Vessels and nerves. The oesophagus is supplied with blood by the 

 divisions given off by the common carotid artery, as well as the bronchial 

 and oesophageal arteries. The nerves are almost exclusively derived 

 from the pneumogastric ; the motor nerves are the superior ousophageal 

 filaments, branches of the external pharyngeal and laryngeal ; the sensitive 

 filaments are derived from the recurrent. 



FUNCTIONS. This canal conveys nutriment from the pharynx to the 

 stomach ; it has no other uses. 



DIFFERENTIAL CHARACTERS OF THE (ESOPHAGUS IN OTHER THAN KOLIrEl) ANIMALS. 



In all the other domesticated animals, the muscular cuat is red-coloured throughout 

 its whole extent, and everywhere ofl'ers the suni'i dcgn of thickness nnd the fame 

 tlaccidity, The canal is also as wido towards the stomnch as at the pharynx. In 

 1,'intiiiHiittf and the Caritivora, it enters the stomach as a funnel-shaped (infinidi- 

 buliform) tuhe. 



The dilatabilily of the oesophagus is very remarkable in these animals : Dogs swnllow 

 large pieces of Hesh ; and Cows and Oxen tire able to inji st large turnips, or sucli 

 voluminous foreign bodies as shoes. 



(In Ruminants and the Curnicora the oesophagus is. proportionally, wider than in the 

 Horse and Pig.) 



COMPAR18OX OF THE (ESOPHAGUS OF MAN WITH THAT OF ANIMALS. 



The esophagus of Man resembles thnt of Carnivoru ; its diameter is almost uniform. 

 It also inclines to the left below the neck, but in tlie tliorax is in tin- nu dian line, though 

 it again deviates to the left as it joins the ttomach. As the thyroid in Mnn is very 

 voluminous, it is related to the oesophagus in the upper part of the neck. Two small 

 accessory fasciculi, belonging to the muscular tunic of the oesophagus, have been 

 described : one is the broncho-cesopliageal muscle, which is detached from the left bronchus ; 

 and the other the pleuro-cetophageal muscle, detached from the left layer of the posterior 

 mediastinum. 



ARTICLE II. THE ESSENTIAL ORGANS OF DIGESTION. 



These organs being all contained in the abdominal cavity, this common 

 receptacle will first bo studied ; afterwards the stomach, intestines, and their 

 annexed organs the liver, pancreas, and spleen will be described. 



THE ABDOMINAL CAVITY. 



In mammalia, the interior of the trunk is partitioned by the diaphragm 

 into two great cavities, that lodge the majority of the organs so vaguely 

 termed the viscera. The anterior, the smallest, is the pectoral or thoracic 

 cavity ; the posterior is named the abdomen, or abdominal </ ihj. The 1 

 the only one we have now to study, is a vast oval-shaped reservoir, elongated 

 from before to behind, having for its upper wall the muscles of the sub- 

 lumbar region, inclosed below and laterally by the muscles of the inferior 

 abdominal region, bounded in front by the diaphragm, and prolonged behind 

 between the bones and membranous ligaments of the pelvis. 



The elements composing the parintcs of this cavity having been already 

 described, we will confine ourselves to an examination of its interior, in 



