894 PRACTICE OF AGRICULTURE. Part III. 



Dealers and breeders aware of this, draw the milk teeth to make their colts appear as horses. It was 

 necessary there should be two sets of teeth, for as they grow slowly in proportion to the jaws; so had 

 there been but one only, the disproportion of growth between the teeth and jaws must have separated 

 them. 



5635. The forms qf the teeth vary more than their structure The incisive or nippers are round, which 

 is favorable for the pressure they undergo ; the upper more so than the lower. On the upper surface a 

 hollow is seen in the young tooth, which, not extending through the whole substance, naturally wears out 

 with the wear of the tooth ; and as a considerable degree of regularity occurs in this wearing away 

 in all horses, it has gradually settled into the general criterion of age. The nippers are not all of them 

 exactly similar ; the corner teeth differ most in being nearly triangular, and in having an internal wall 

 or side, which does not become level with the rest until long after the others. The cuspidate tusks or 

 tushes are permanent, appearing at about five years or rather earlier ; those in the front jaw are usually 

 nearer the nippers than those below. Each presents a slight curve, which follows the direction of all 

 the canine or pugnatory teeth of other mammalia. The pointed extremity wears away by age, leaving 

 merely a buttoned proces.s,|which may serve as a guide to the age when a horse is suspected to be bishoped, 

 as it is called, from a man of that name who was peculiarly dexterous in imitating on old teeth the dis- 

 tinctive cavity of youth. The molar or grinding teeth are stronger in the upj)er than in the lower jaw; 

 which was necessary, as they form the fixed point in the process of grinding. The upper surface pre- 

 sents nearly a long square, indented from the alteration of the enamel with the bony portions ; and as 

 the interior or upper teeth hang over the posterior, so the ridges of the one set are received into the 

 depressions of the other. 



3636. Wear of the teeth. The teeth, in a state of nature, would probably present a surface opposed to 

 each other for mastication, to the latest period of the most protracted life ; but the removal of the animal 

 from moist food to that which is hard and dry, must occasion an unnatural wear in those organs ; and 

 hence, although the teeth of the horse, even in a domesticated state, are not subject to the caries of the 

 human ; yet the grinders are liable to become thus injured by continued exertion. In the young or 

 iidult horse, the upper and under grinders do not meet each other horizontally ; on the contrary, they have 

 naturally an inclination obliquely inwards; and those of the upper jaw present small si).ices between each 

 other, while those of the lower are more continuous: by which means as the food, but particularly as 

 interrupted portions, as grain, become ground, they fall within the mouth to be replaced ujider the grind- 

 ing surface, if necessary, by the joint action of the tonjjue and muscles of the cheek. This arrangement 

 becomes in a great measure frustrated in old horses, by the superior wear of the inner surface of the 

 upper grinders, as well as by the general misapplication of the surfaces of both upper and under te:'th^ 

 by constant attrition when worn down to the gums nearly. The unfortunate animal feels sensible of this, 

 and endeavours to remedy it by throwing the wear on the outer edge, by an inclination of tUa'ower jaw 

 and of the head in general ; and which is so particular in its ajjpearance as to engage the attent:o!i of the 

 by.standers. This defect may be in a considerable degree remedied by casting the animal, and having 

 opened and wedged the mouth so as to keep it so, with a well-tempered concave file, to remove the in- 

 equality as much as may be. When the defect is considerable, and the horse is mild and quiet, it is 

 better to file the inequalities every day, which will gradually but efTectualljfwear them down. It how- 

 ever happens, that the inclination thus to wear is commonly resumed, and gradually the same loss of 

 nutriment takes place: in which case, soft moist food, as carrots, mashes, soiling, or grazing, must be 

 substituted for harder substances, and if corn be actually necessary, let it be bruised. Whenever an old 

 horse betrays symptoms of want of condition, or weakness and emaciation, that neither his mode of 

 feeding, nor his ratio of work will account for, and particularly if whole grains should be found in his 

 dung, his teeth should be examined carefully. This undue wearing of the teeth occasions another evil 

 often, which is ulceration of the cheeks, by reason of the projecting ragged surface of the uneven teeth, 

 which can only be remedied by the removal of such portions. These projecting portions are called by 

 farriers wolves' teeth. 



SuBSECT. 2. The Anatomy of the Trunk. 

 5637. The trunk of the skeleton consists of the spine, the pelvis, and the thorax or 

 chest, composed of the ribs and sternum. 



5638. The bony column called the spine, is made up of seven cervical, eighteen dorsal, six lumbar, and 

 five sacral vertebrae, with the addition of thirteen or fourteen small tail-bones. The spinal bones are 

 thus divided on account of the varieties they present ; they have, however, some characteristics in com- 

 mon. Each is composed of a spongy bony body, with protruded points called ])rocesses, which processes 

 unite to form a hollow through which the spinal marrow is transmitted ; and by some of these processes 

 the vertebraa are articulated with each other, as well as by their bodie^s, by which their strength as a 

 column is much increased. Though but little motion exists between any two vertebrae, yet the flexibility 

 of the whole spine is considerable. 



5639. The ceruical or neck vertebra; {g, h), are called by farriers and butchers, the rack bones. It is 

 remarkable that, let the neck be long or short, the number of bones is the same in most quadrupeds. 

 The first and second differ from the rest in figure, and present some other peculiarities. The first is the 

 only one of them to which the great suspensory ligament of the neck does not attach itself, which would 

 have interfered with freedom of motion. It articulates with the sc^cond by receiving its tubercular pro- 

 cess within it, and from which process the second of these bones has been called dentata. Between these 

 two neck bones is situated a part, where the spinal marrow is exposed from any bony covering ; at 

 which part butchers plunge a pointed knife into what they call the pith of the neck, when they want to 

 kill their animals instantaneously, and without effusion of blood; from whence it is called pithing. The 

 remaining five neck bones are not very dissimilar from each other. 



.5640. The dorsal vertebrcB {y) are now and then, though rarely, nineteen in number; Ihey do not 

 differ materially from each other, but in the length of the spinous processes of the first seven or eight. 

 It is to these elongated spines that we owe the height of the withers, and as the intention of these parts 

 seems principally to serve as levers for the muscles of the back inserted into them ; so we can readily 

 understand why their increased or diminished height is favorable or unfavorable to progression. These 

 like the former articulate with each other by processes as well as by the anterior and posterior surfaces 

 of their bodies; between each of which is interposed a substance semi-cartilaginous in its structure, which 

 is most compressible at its sides, these permitting the motion of the spine. 



5641. The six lumbar vertebrce differ from the foregoing in having a longer body, and very long trans- 

 verse processes to make up for the deficiency of ribs in the loins. These bones often unite by (he pressure 

 of heavy weights, and sometimes spontaneously by age, and thus we need not be surprised at the stiffness 

 with which some old horses rise when down. 



5642. The five sacral vertebrae (x) are united into one to give strength to the column, and to serve as a 

 fixed support to the pelvis, or basin, with which it is interwedged. From this detail it will appear how 

 admirably this spinal column is adapted to its important functions of serving as a flexible but powerful 

 .support to the machine; and how by the formation of a large foramen within the substance of each 

 vertebra, a bony canal is offered for the safeguard of the spinal marrow, from which, through lateral 

 openings in these vertebra the spinal nerves are given off in pairs. The pelvis or basin (2) is composed of 

 the sacrum, the two ossa innominata and coccygls. The ossa innominata in the foetal colt before birth 

 are each composed of the ilium, the ischium, and the pubis, before birth all traces of this division are 



