THE HORSE. 



91 



parotid, the submaxillary, and the sub- 

 lingual. 



" The parotid, the largest of these glands, 

 so called from being placed near the ear, 

 lies within a hollow space at the upper and 

 back part of the head, bounded by the 

 branch of the lower jaw before, and the 

 petrous portion of the temporal bone behind : 

 it extends as high up as the root of the ear, 

 and as low down as the angle of the jaw, 

 by which latter a small portion of it is con- 

 cealed. This gland, like the others of the 

 same class, is enveloped in a case of dense 

 cellular membrane, and is constituted, in 

 structure, of many little lobes or lobuli, con- 

 nected together by processes transmitted 

 into the interior from this cellular covering. 

 Every lobulus is composed of a distinct set 

 of secretory vessels, from which numerous 

 tubuli arise, conjoin, and at length form one 

 main branch ; these branches, which corre- 

 spond in number to the lobuli, unite and 

 re-unite until they end in one common ex- 

 cretory duct. The duct emerges from the 

 inferior part of the gland, runs along the 

 inner part of the angle of the jaw, and 

 crosses over the posterior edge of the bone 

 immediately above or behind the submaxil- 

 lary artery and vein : in the remainder of 

 its course it corresponds to the border of 

 the masseter, and, about opposite to the 

 second anterior molar tooth, pierces ob- 

 liquely the buccinator, and terminates by a 

 tubercular eminence upon the internal sur- 

 face of the buccal membrane.* 



" The submaxillary gland, of smaller 

 volume than the parotid, lies in the space 

 between the angles of the jaw, to which, and 

 to the muscles thereabouts, it is loosely 

 attached by cellular membrane : a portion 

 of it is also generally found proceeding 



* To expose this duct, at or near its issue from the 

 gland, an incision should be earned along the posterior 

 border of the branch of the lower jaw : first, dividing the 

 skin ; secondly, the panniculus ; thirdly, the cellular tissue 

 immediately covering the duct, which is readily dis- 

 tinguished by its glistening pellucid aspect. By extending 

 the incision around the angle of the jaw, directing it 

 towards the inner edge of the bone, the duct will be found 

 making its first turn : here, however, it is lodged in a 

 hollow, deeply buried in cellular tissue. 



backward as far as the trachea. Its struc- 

 ture 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 gland, and 

 terminates by a little mammiform elongation 

 of membrane, vulgarly called the barb (bar- 

 billon) or pap, upon the frsenum linguae, 

 about half an inch above its attachment to 

 the symphysis. Among the other ridiculous 

 and miscliievous practices of farriers is that 

 of snipping off these processes. They 

 were seemingly designed as valves, to pre- 

 vent the insinuation of alimentary matters 

 into the ducts. The coats of this vessel are 

 extremely thin and translucent. 



" The sublingual gland is still smaller in 

 volume than the submaxillary, though, al- 

 together, 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 freenum linguEe. 



" 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 ; anteriorly, 

 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. 



