972 PRACTICE OF AGRICULTURE. Part III. 



SUBSKCT. 10. The. Cavity of the Mouth. 

 r.Ni. The external puts ,,/ the month arc the lips, cheeks, and beard. The lips are maile up of fleshy 



manes SO disposed J- to give them motion every way ; they arc covered over with a very line expulsion 

 of skin almost devoid of hair, their exquisite sensibility forms them into an organ of touch ; and in this 

 point of new they may be considered as supplying the part of the points ofthe Angers in man. The checks 



an- equal!) muscular and vcable, but arc more furnished with hair ; and the beard, ill addition to this 



thin hairy expansion, has a set Ol long hair-. 



6 BS the internal part* qf the mouth are the teeth already described (G2(X).\ the Bums, the alveolary 

 edges, the palate, the tongue, and the parts of the great posterior cavity. The gums are a spongy sub- 

 stance win. h embraces and holds last the teeth in their alveolary sockets. The membrane which covers 

 the gums at the lower part of the channel forms a kind of fold to connect and confine the tongue on each 

 side These folds arc called the barbs, and are apt to be mistaken and cut off as excrescences. The bars 

 are the spaces in the jaw left between the grinders and nipper teeth ; and which man, ever ready to take 

 advanl ige of for his own purposes, has made use of to ensure obedience by placing on its sensitive surface 

 the pressure of the bridle-bit The palate forms a bony arch, covered by membranous folds, which are 

 apt, when the stomach is affected, to become swollen, in which case the horse is said to have the lainpas 

 or tampers. (6446.) Uy means of these rugose folds, the food is retained within the mouth. The curtain 

 oj the palate or vilum paluti, which is situated at the extreme end of the palatine arch, is stretched 

 directly across the hinder mouth, and is not intercepted as in man by the pendulous body termed uvula. 

 This palate curtain is intended to shut out the communication between the mouth and the great cavity of 

 the fauces, winch it does at all times, except when the horse is swallowing, at which period the curtain 

 i- forced back and the food passes. From this cause likewise the horse is prevented from breathing but 

 by Ins nostrils; and when any air does pass by the mouth, as in coughing, crib-biting, Arc. it is only 

 effected by a forcible displacement of the curtain. 



6383. The tongue is a long fleshy mass (fig. 831 e), which adapts itself below to the form of the channel, 

 and above to the arch ofthe palate : its external surface is rough by means of papilla?, which are inclined 

 backwards, and thus resist the loss of the food received within the mouth. In some animals, as the ox, 

 bear, &c, they are very large, and in the cat pointed. The tongue is a very principal organ in mastica- 

 tion, carrying, by its great mobility, the food into every direction until fully acted upon, and finally 

 passing it into the pharynx. 



6384. Sense of tasting. It is not observed that this sense is so diversified in brutes as in man ; but it 'is 

 instinctively so correct, that it seldom errs in the herbivorous tribes ; and when it does, there is reason 

 to suspect some present defect in the organ, arising from morbid sympathy, which (as in the instance of 

 salt-water, of which at some times horses w ill drink immoderately,) prompts them to take in matters they 

 are accustomed to refuse. Taste was given to brutes to regulate their other senses, and thus there are 

 few plants or substances whose application to the tongue, under ordinary circumstances, produces an 

 agreeable effect but such as are proper for food. Nature, therefore, stimulates her creatures to search fur 

 edibles by a double motive, the calls of hunger and the pleasures of taste ; and these are usually in unison, 

 for the nausea of repletion destroys the appetite of taste. 



6JS5. The pharynx. The cavities ofthe mouth and nose terminate in the groat cavity of the fauces 

 called by this name, to which also is appended another lesser opening called the larynx, immediately ap- 

 propriate to the entrance of the trachea or windpipe. Within this great chamber, at the afterpart of the 

 mouth, shut from it by a membrane only, is the Eustachian cavity, into which the Eustachian tube opens, 

 ami which great membranous hollow is unknown in man and most quadrupeds {fig. 831. d.) Its use is not 

 understood, but it is probably connected with the voice. 



638<i. The larynx is situated at the posterior part of the former cavity, and appears as a cartilaginous box 

 between the os hyoides, to which it is attached for support. This cartilaginous box, or entrance to the 

 windpipe, is formed of several pieces, and is furnished with a kind of movable door, which, in ordinary 

 cases, exactly fills up the cavity left by the arch of the palate curtain, thereby shutting the cavity of the 

 mouth, and forcing the animal to breathe through his nasal openings. In extraordinary cases, as when 

 the animal swallows food, this cartilage is forced down, and then it becomes a door to the glottis or funnel 

 part of the trachea, and thus prevents the entrance of extraneous matter into the lungs. All these parts 

 are operated on by numerous muscles. 



6387. The voice. The larynx has also another important office in being the organ of the voice. The 

 cartilages of the larynx are very movable on one another, and are furnished with muscular cords, which 

 tighten or relax them ; besides which, they are also furnished w ith peculiar and appropriate sacs or cavi- 

 ties, independent of the tracheal opening, and which are of different magnitudes and directions in different 

 animals. The cartilages of the larynx being acted on by the cordae vocales, produce different degrees of 

 density, and consequently different degrees of expansion in the laryngeal sacs; by which, either in expir- 

 ation or inspiration, are produced different degrees of vibration, and consequent intonation. Neighing 

 appears produced wholly by expiration through the nose, as are most of the tones of the horse's voice. 

 This is proved by slitting the nasal cartilage, which wholly stops it. Knuckering,as it is termed, is onlv a 

 lesser neigh, with shorter, deeper, and less forcible tones. The former sound is used as a call, the latter 

 as either call or recognition. It is likewise, when used mildly, significant of joy and affection, and is then 

 beautifully sonorous. The horse has an acute sound produced by inspiration, usually descriptive of lust : 

 in most other cases his intonations are accompanied by expirations ; nor does it appear that the tongue or 

 tec ill of the horse are much concerned in the modulations of his voice. 



i> 188. The parotid glands, or, in the language of farriers, the vives, are two considerable bodies on each 

 side of the head, extended from the base of the ear around the angle of the jaw. Each parotid is a con- 

 glomerate (.-land, turn shed with numerous little ducts, which unite into one, and enter the mouth about 

 the second molar tooth. These glands furnish saliva for the use of the mouth, and it is an induration 

 and gathering, either in them or the maxillary glands, which form the strangles of voung horses. 

 Assistant to these in the furnishing of saliva are the maxillary glands, situated within the branches of 

 the lower jaw, and the sublingual also. 



Subsect. 11. Tlie Xeck. 



6589. The external parts ofthe neck are the common coverings which have been described ; the cervical 

 ligament, the muscles, and the jugular or neck veins, &c. The cervical ligament (fig. 831. i), is a very 

 strong substance, in some parts semimuscular, and in all extremely elastic, stretched from the occipital 

 bone along the back of all the cervical vertebra? except the first Continued on the spinous processes of 

 the dorsal vertebra?, it fills up the dip or depression of the spinal column of the neck, so completely as to 

 form the neck either into a plane, or an elegantly convex line upwards. By its extreme tenacity, the 

 ponderous mass of the head is preserved in its situation, without the necessity of an immense mass of 

 muscle which would, without this contrivance, have been necessary. It is to "an injury received at the 

 upper and anterior part of this ligament, that the pole evil is owing. The muscles of the neck are too 

 numerous to allow of particularisation : it is sufficient to say, they most of them run longitudinally. The 

 jugular veins run one on each side ofthe neck superficially, on the side ofthe trachea and windpipe, and 

 form the vessel usually bled from (fig. 833. r). A few inches before they reach the angle of the jaw, each 

 dn ides to famish the head. 



6390. The internal parts of the neck are the vertebra, within which passes the spinal marrow. The 

 carotid arteries pass up under the jugular veins, near the resuphagus I fig. 833. s). The trachea or wind- 



