The Horse's Mouth, Showing the age by the teeth

by Edward Mayhew

The next wood-cut exhibits the molar a, immediately after it has lost its covering. At this time the table is very uneven, presenting points which the finger would readily recognize, but in a short time these wear off, and an even surface is obtained, rendering it level with the other teeth, b b.

As is here seen, when the crown has been removed, the permanent molar is well up, although it occupies the same place, and fills the same alveolar cavity which the temporary molar originally held. The horse incisors do not occupy the same cavities in which the milk incisors were placed, but are developed in cells formed especially for their reception, and come up rather behind than absolutely under the primary teeth. The form of the anterior part of the jaw in the foal admits of such an arrangement, and its greater comparative bulk gives all the space that was required. The space, however, between the branches of the lower jaw where the molars are developed, is filled by important muscles; and while any thickening externally would deteriorate from the symmetry of the head, any internal enlargement would have interfered with the free motion of the tongue and hyoideal appendages, the movements of both being as essential to perfect mastication as the presence of the teeth themselves. Hence the grinders are in their development regulated by a different law to the incisors; nor is the ordinization which declared the first should be well up, and the last scarcely to be seen when the period for casting off the temporary teeth arrived, to be passed over in silence. The molars are more important to the welfare of the animal than the incisors can be supposed to be. If the front teeth are irregular, the horse, nevertheless, can manage to feed; and if some are even wanting, the animal can subsist. A few would serve to grasp a sufficiency of food, especially such food as the state of the mouth, during the period of dentition, would dispose the colt to partake of. The animal is then in an inflammatory condition—the system is excited—and it is a wise provision which leaves the creature inclined only, at such a time, to consume a soft and laxative herbage, not in too great a quantity. The molars, on the contrary, if irregular in their growth, or uneven upon their surfaces for any lengthened period, would produce great local pain, and much constitutional disturbance. The food, in consequence of the rugged condition of these teeth, would be imperfectly masticated, the organs of digestion would become impaired, and the whole frame would suffer. To prevent this, the molars are fully cut before the temporary tables are cast off, nor do both the tables leave the mouth at the same time. The one on the upper jaw is first shed, and it is not until this has, by attrition, been rendered somewhat flat, so as to present a surface upon, or against which the food can be ground that the permanent molar of the lower jaw is uncovered. The unevenness of the grinding agent becomes now of less moment, since the part over which it is to be moved has been rendered fit for its uses, and since there are other teeth that present all their surfaces, suited for the purposes of mastication.

34. The manner of examining the teeth is simple enough, and yet a few remarks may as well be made upon this part of the subject. To see the incisors, all that is necessary is to part the lips; but many horses are naturally shy when their mouths are touched, and more are rendered so by unnecessary severity in the administration of medicine, or by the tricks to which they may have been subjected. A certain degree of caution is always needed when an animal is strange to the examiner. Where the horse shows a disposition to resist, the groom who attends upon it, if present, should be allowed to handle the mouth, the judge being content to look and form his opinion from what he sees. If the groom be not in the way and the horse seems nervous, let the neck be patted, the face below the eye gently rubbed, then the nose caressed; and when the timid animal is assured that no harm is intended, the lips may be freely drawn asunder: but should the head be snatched away, when the first attempt to see the teeth is made, let the hand immediately release the mouth, rather than endeavour to retain the hold. It is far better to begin again than justify the fears of the horse, by a needless and worse than useless struggle, which in the end will probably be of no avail. After the horse has by forbearance been rendered quiet, while the lips are held asunder, the shape, colour, length, and obliquity of the teeth are noted, and the presence or absence of milk teeth observed. When this is done without violence, the animal will not often offer any opposition to the finger being introduced to feel the tushes, or to the sides of the mouth being separated so as to obtain a fair view of them. The examiner now places himself in front of the horse, and by introducing one finger behind the incisors and getting it under the tongue, will cause the animal to open its mouth, or the tongue may be seized and drawn out of the mouth; and if confidence is established, no opposition will be offered to the jaws being kept for a short time apart. Of this, advantage is taken to observe the arrangement of the teeth, to inspect the tables, and to note the shape or depth of the infundibula. When all this has been accomplished, in less time perhaps than it takes to read a description of the process, the business is generally finished, and a conclusion has been arrived at that amounts to positive conviction. On certain occasions, however, it may be desirable to inspect the molars; and to do this properly requires a little tact. Some persons cast the horse for this slight operation: indeed, there are people who throw horses as though they imagined nothing could be done without the hobbles. There is, however, generally no occasion for such a proceeding; the twitch in the great majority of cases is all that is needed, and, with a little patience, even that instrument of torture may be dispensed with. A stool, or if nothing better is at hand, the stable pail is fetched for the operator to stand upon, so as to look with ease into the mouth of the elevated head. The animal is led into a good light, the balling iron placed between its jaws to keep them asunder, the tongue being drawn out to the side, removed from that which it is desired to inspect. While the mouth is thus distended, the person who is to judge, mounts the stool or pail, and looks into it till he is satisfied. Should the operator be desirous of feeling the teeth, he descends from his rostrum, and having pulled off his coat and bared his arm, introduces it into the mouth, while the tongue is drawn to one side by the assistant who holds the iron; always, however, taking care if possible, to have a balling iron which is open on one side, the arm being so introduced that the elbow is towards the free space. Should this precaution be neglected, if the horse prove suddenly restive, an accident may ensue. The lower jaw being easiest felt, and the teeth therein situated being most readily counted, that is the part generally manipulated. This is not difficult unless made so, and often rendered dangerous by the intemperance of the party who undertakes to accomplish it. Having described it, the author will now proceed to state the times at which the different teeth appear, and the signs which they exhibit.

35. At birth the foal has usually three molar teeth on either side of each jaw,* and perhaps two front incisors, which last are then lateral in situation, and appear to be very large in proportion to the age of the animal. It is, however, usually a fortnight or three weeks after birth before the incisors appear. I have to acknowledge the greatest obligations to the Messrs. Tattersall, for the valuable opportunities afforded me of inspecting blood stock, at their large and admirably-conducted establishment at Willesden Paddocks.

* The wolf’s teeth at the anterior of the two rows of upper molars are generally present or indicated at birth; but as they are not invariably found, and are by no means to be depended upon as significant of the age, no direct notice need be taken of their existence.

36. At six weeks, two more incisors are generally cut in either jaw, and those which originally seemed to grow from the sides, have, by this time, taken a position more directly in the front of the mouth.

37. At six months, the incisors have moved almost into the situation they will hereafter occupy, and the jaw appears somewhat elongated; but, if the gums be observed, it will be seen that nature is preparing to cut the corner milk teeth, which may even be through the gum.