240 DIGE>TIVE SYSTEINI. 



ceding backward as far as the trachea. It structure is similar 

 to that of the parotid gland. The submaxillary duct issues near 

 the centre of the gland, creeps along the under and inner border of 

 the tongue, close to the lower edge of the sublingual <,land, and 

 terminates by a little mammiform elongation of membiane, vul- 

 garly called the barb (barbillon) or pap, upon the frsenum linguae, 

 about half-an-inch above its attachment to the symphysis. Among 

 the other ridiculous and mischievous practices of farriers is that of 

 snipping off these processes. They were seemingly designed as 

 valves, to prevent the insinuation of alimentary matters into the 

 ducts. The coats of this vessel are extremely thin and translu- 

 cent. 



THE SUBLINGUAL GLAND is still smaller in volume than 

 the submaxillary, though, altogether, one much resembles the 

 other in figure. It lies along the under part of the tongue, covered 

 by the buccal membrane, where, from the lobular unevenness it 

 gives to the surface, its situation is well marked. Its ducts 

 penetrate the membrane by the side of the fraenum linguae. 



The use of the salivary glands is to secrete a saline limpid 

 fluid, called saliva; which is conveyed and poured by their 

 ducts into the mouth during manducation : here it is mixed with 

 the food, mollifying it and rendering it more easy of digestion, 

 and at the same time facilitating the passage of the alimentary 

 bolus into the stomach. 



OF THE PHARYNX. 



The pharynx is a funnel-shaped sac, lodged in the throat for 

 the reception of the food. 



Situation. — The pharynx is contiguous to the guttural pouches, 

 superiorly ; the larynx, inferiorly ; and the anterior portions of 

 the parotid glands and branches of the jaw, laterally. Posteriorly, 

 it is continuous in substance with the esophagus: anterioily, it 

 presents an opening to the mouth. 



Attachment. — In front, to the os hyoides and palate bones ; 

 below, to the larynx ; behind, it grows narrow and ends in the 

 esophagus. 



Structure. — The pharynx is in part muscular and in part mem- 

 branous. Of the muscles belonging to it (described at page 100) 

 the constrictors are those that more immediately enter into its 

 composition. They are so disposed as to give the membrane 

 forming the sac a complete fleshy covering, which is rendered 

 the more uniform by their proximate fibres being indistinguish- 

 ably blended : thus the muscles form the most substantial part 

 of the pharynx. The lining membrane, which is of the mucous 

 class, is soft and thick in substance, and palely tinged with red 



