THE SALIVARY GLANDS. 205 



drivel from the mouth. This disease often exists without the nature of it 

 being suspected. If the mouth is opened, one large bladder, or a succession of 

 bladders, of a purple hue, will be seen extending along the whole of the under 

 side of the tongue. If they are lanced freely and deeply, from end to end 

 the swelling will very rapidly abate, and any little fever that remains may 

 be subdued by cooling medicine. The cause of this disease is not clearly 

 known. 



THE SALIVARY GLANDS. 



In order that the food may be properly comminuted preparatory to diges- 

 tion, it is necessary that it should be previously moistened. The food of the 

 stabled horse, however, is dry, and his meal is generally concluded without any 

 fluid being offered to him. Nature has made a provision for this. She has 

 placed in the neighbourhood of the mouth various glands to secrete, and that 

 plentifully, a limpid fluid, somewhat saline to the taste. Tliis fluid is conveyed 

 from the glands into the mouth, by various ducts, in the act of chewing, and. 

 being mixed with the food, renders it more easily ground, more easily passed 

 afterwards into the stomach, and better fitted for digestion. 



The principal of these is the parotid gland (see cut, p. 173). It is placed 

 in the hollow which extends from the root of the ear to the angle of the lower 

 jaw. A portion of it, q, is represented as turned up, to show the situation of 

 the blood-vessels underneath. In almost every case of cold connected with 

 sore throat an enlargement of the parotid gland is evident to the feeling, 

 and even to the eye. It is composed of numerous small glands connected 

 together, and a minute tube proceeding from each, to carry away the secreted 

 fluid. These tubes unite in one common duct. At the letter u, the parotid 

 duct is seen to pass under the angle of the lower jaw, together with the 

 submaxillary artery, and a branch of the jugular vein, and they come out again 

 at w. At r, the duct is seen separated from the other vessels, climbing up the 

 cheek, and piercing it to discharge its contents into the mouth, opposite to the 

 second grinder. The quantity of fluid thus poured into the mouth from each 

 of the parotid glands amounts to a pint and a half in an hour, during the action 

 of mastication ; and, sometimes, when the duct has been accidentally opened, it 

 has spirted out to the distance of several feet. 



The parotid gland sympathises with every inflammatory affection of the 

 upper part of the throat, and therefore it is found swollen, hot, and tender, in 

 almost every catarrh or cold. The catarrh is to be treated in the usual way ; 

 while a stimulating application, almost amounting to a blister, well rubbed over 

 the gland, will best subdue the inflammation of that body. 



In bad strangles, and, sometimes, in violent cold, this gland will be much 

 enlarged and ulcerated, or an obstruction will take place in some part of the duct, 

 and the accumulating fluid will burst the vessel, and a fistulous ulcer be formed 

 that will be very difficult to heal. A veterinary surgeon alone will be com- 

 petent to the treatment of either case ; and the principle by which he will be 

 guided, will be to heal the abscess in the gland as speedily as he can, and, pro- 

 bably, by the application of the heated iron : or, if the ulcer is in the duct, 

 either to restore the passage through the duct, or to form a new one, or to cut 

 off the flow of the saliva by the destruction of the gland. 



A second source of the saliva is from the submaxillary glands, or the glands 

 under the jaw. One of them is represented at s, p. 173. The submaxillary 

 glands occupy the space underneath and between the sides of the lower jaw, 

 and consist of numerous small bodies, each with its proper duct, uniting to- 

 gether, and forming on each side a common duct or vessel that pierces through 

 the muscles at the root of the tongue, and opens in little projections, or heads. 



