Chapter II: Part 2

18. _To distinguish an upper from a lower molar tooth_ is not difficult. The presence of the infundibula in the first would alone enable it to be pointed out; but there are other indications that are worthy of a passing notice. The table of the upper molars is much broader, being compared to those of the lower jaw as nine is to five. Then the form of the table is different in each. The table of the lower tooth is indented on either side, the indentation extending downwards along the fang. The table of the upper molars present two narrow prominences, and two broad grooves on the outer side; and also exhibits one broad prominence upon the centre of the inner side--all of these developments being likewise contained along the fang. The slant of the tables also differs. In the upper jaw, the outer edge is the lowest. In the lower jaw, the tables incline in the opposite direction.

19. _The teeth of the horse are very firmly implanted in the jaws._ The fangs are of a length which they who have only seen the teeth extracted from the mouth of a human being would hardly imagine. The length of fang of course gives the teeth some security; but this is not the only provision made for that end. The teeth radiate towards a common centre, being widely separated at their roots, but approximating at the crowns. They also incline laterally from the perpendicular, so that the force applied to them never acts in a direct line, or is concentrated upon one particular point.

20. _The molars of the lower jaw are the active agents of mastication_, for motion, during this process, only takes place in that part of the head in which those teeth are placed. The inferior molars are the instruments that grind--the upper molars are simply the surfaces upon which the food is ground. The whole of the molars, however, are never simultaneously employed. The horse can chew but on one side at a time, for as the inferior maxillary bone is considerably narrower than the superior, if the teeth on one side are brought into apposition, those of the opposite side are necessarily separated. Any one who has observed a horse feeding, will have remarked that the animal, during the act, continually abducts and adducts, the lower jaw not causing it to describe a circle, as does the cow, but urging it first to one side and then to the other. It will be seen, therefore, that the whole force of those strong muscles, which close the mouth of the horse, is employed on a portion of the jaw at the same moment, and the power then exerted must obviously be very great. Recognizing this fact, the reason for all that has been pointed out--the shelving tables--the grooved or indented sides--the double inclination, and the great length of the fangs is at once perceived, for the action is a wrenching one; and the greater extent of, and more uneven, surface presented by the molars of the upper jaw, facilitates the comminution, without imposing weight upon the muscular activity. Had the larger teeth been implanted in the inferior maxillary bone, the labour imposed would have been much augmented, and the end attained have been in no way expedited.

21. _Provision has been made by Nature to meet the wear to which the horse's teeth are subjected._ Such provision, however, I am of opinion, has been somewhat mis-stated by the majority of writers who have treated of this matter. Many of these authors dwell greatly upon the growth of the teeth of the horse, as though this function were in constant activity during the life of the animal. The arguments by which their views are supported, are primarily drawn from analogy rather than deduced from observation. Because the teeth of certain animals, especially those classed by naturalists as rodentia, and of which the rat and rabbit are familiar types--because the teeth of these creatures are known to grow, and those of the elephant are also proved to increase--the same is assumed of the horse. The inference is certainly of strength, but nevertheless it is far short of proof; a similarity between the animals is not demonstrated, and a sameness cannot be shown. Moreover, in another direction, an evidence is attempted to be made of the consequence which ensues when one of the molar teeth loses its vitality; the tooth that so suffers is rapidly worn down, and the opposing tooth becomes of an unnatural length, projecting far beyond its fellows. The increase of length in such a case has been supposed to go on in the sound organ at the natural rate, and the growth of the diseased tooth only has been thought to be stopped; hence the amount of wear and of growth is attempted to be measured; but on consideration it will be seen, that something more than the mere cessation of increase has to be calculated. The carious tooth had ceased to be a part of the living body, and with its vitality the organ lost its capability of self-preservation. The condition of the part had changed, and of the strength which vitality bestows, all persons must be conscious. To argue from the results produced upon dead matter, and then apply the deductions to living organs, is a course which no physiologist will sanction. The tooth that had ceased to live, might be quickly worn down, for other reasons than that it had ceased to grow. This is so clear, and the inference to which allusion was formerly made so obviously untenable, that I shall not longer detain the reader by dwelling upon either, but proceed to state my own views of the subject. I admit the teeth of the horse do grow, and only doubt if the process has been properly described. When the crown of the tooth first appears in the mouth, the fang is not completed, and the root has not even been developed. The horse is seven years old before all the roots are perfected, and when these are completed, I doubt if the after growth is material. If the jaw of an old horse be examined, the alveolar cavities will be found to be shallow, showing that the loss, consequent upon the wear, was compensated by the tooth being projected into the mouth, and not by any increase of substance. Again, those animals, the incisors of which retain the marks in extreme old age, may show long teeth, but not of that excessive length which growth would suppose; only such as the want of wear would occasion, supposing the increase to cease when the root was perfected. The fang, in fact, is so much tooth in reserve, and as such answers the purpose for which growth was supposed to be necessitated. I have by me, specimens of old teeth, but the measurement of none of them contradicts the opinion I have advanced, there being but a material increase of the crusta petrosa, which at the root blends with the ivory, and cannot be clearly separated from it. The thickening of the crusta petrosa around the root and neck, probably never ceases during the health of the animal; but to this substance alone is confined the imaginary growth of the horse's teeth. When the roots are perfected, the length of the tooth is completed, and the only after process consists in a gradual deposition of earthy matter, within the body of the member, the bulk of which is defined. In old teeth, the ivory becomes very dense; and he who attempts to cut through an old and young tooth, will be made aware of a contrast. The pulp in the teeth, after the formation of the root, gradually diminishes and ultimately disappears, in consequence of the ossific deposition. In fact, when growth ceases, consolidation has taken place, and rendered its continuance no longer necessary.

22. _The cavity of the pulp_ has been always stated to exist in the tooth of the horse. In the human tooth it occupies the extremity of the fang, being situated within the substance of the ivory; and the double teeth are known to have as many cavities of this kind as there are roots to the part. The same has been assumed to be the case also with the horse, but I cannot say that investigation enables me to corroborate this opinion. I find no cavity, that is no empty space, constantly present in the fangs of the horse's teeth, and no separate or defined cavities at the roots of the molars. The bone or ivory may be deficient, more or less, towards the centre of the fang; but this space, not yet occupied by the osseous deposit, is filled by a membraneous substance which is continuous with the crusta petrosa of the root, and will ultimately be converted into bone. I cannot separate the tissues forming the pulp, from the crusta petrosa itself; and I assume the two to be continuous. The only difference I can observe is, that the tissue of the pulp is the finest; but as the vessels of the one primarily pierce through and ramify upon the other, I cannot perceive the necessity for their separation. It will be understood, that I am speaking of these parts in a fresh subject, and not alluding to a mascerated and dried specimen, the appearance presented by the last being calculated to mislead. With age, the pulp diminishes; and in a tooth extracted from a very old animal, no positive remains of it will be found--osseous matter filling up the space which the pulp once occupied.

23. _Nature provides the horse with two sets of teeth._ The first are small, or of a size proportioned to the diminutive stature of the foal, and are called milk teeth--colt's teeth--or temporary teeth--either of which terms equally well characterizes them. The temporary teeth are twenty-four in number--six incisors in either jaw, and three molars on both sides of the upper and also of the lower jaw. The incisors sometimes begin to appear in the mouth before birth, though generally the gums are unbroken when the foal is dropped; they commence to be shed when the colt is two years and a half old--none remaining in the jaws after the fifth year. The molars, which are the first, second, and third, or the anterior three, begin to be cast off at two years and a half, being entirely removed between the third and fourth year. It used to be asserted that the last temporary molar was shed between the fourth and fifth year of the animal's life; but while I was connected with the Veterinary College, I inspected several heads and found none that corroborated the doctrine, which, for half a century, had been inculcated at that Institution. My observations were at first violently contested, and opportunities were sought to uphold the received and old manner of teaching. By slow degrees, however, the truth prevailed; and I have now the pleasure of knowing, that what I pointed out to the professors, those gentlemen at present communicate to their pupils. Several parties, however, have been mean enough to pretend they either are ignorant of what I effected, or believe what I accomplished was the work of another person; while I am sorry to add, that a professor has even gone so far as to lay claim to a discovery, which at the time cost me some pains to fully make out, and more to firmly establish. My observations were, in the first instance, made alone, and the only person who eventually assisted me was Mr. I. K. Lord, of Tavistock. That gentleman did afford me much help, and to him I beg publicly to record my sense of obligation. No other individual was in any manner concerned in the investigation, and I regret that I should be necessitated to make such an assertion. The point, however, is now fully established; and it will be seen, that it may be of practical importance. The molars, as truthfully as the incisors, denote the age; and, as corroborators, they should, in every doubtful case, be inspected.

24. _To know the temporary from the permanent teeth_, or to be able to distinguish one from the other, is very essential; but such knowledge is not so common as may be generally imagined. Dealers have blundered, and many a gentleman having purchased a yearling for a horse, has afterwards been surprised to discover that the animal was losing some of its front teeth. These kind of mistakes are mostly confined to the smaller breeds--with ponies the incident is common enough, but even with horses it has occurred. I may therefore be excused if I enter rather minutely into those points of difference which distinguish the one from the other. The reader must be content to study well this portion of the treatise, for the age is best marked by the number of milk teeth retained in the jaw, and easiest told during those years when these teeth are in the course of being shed.

25. _To recognize a milk incisor tooth_ the reader must bear in mind that it is of a temporary nature, and intended only to exist during the few first years of the animal's life, or during its colthood; for when all the permanent teeth are fairly up, the creature becomes a horse. The recollection of their temporary character will cause them to be the more easily distinguished: they look less solid and less firm; they are smaller, more white, and if ideas of beauty and sentiment befit such a subject, have a prettier and more innocent appearance. This is perfectly true as a general rule, but nevertheless must not be absolutely applied; for I have seen rare instances in which the milk teeth were, from constitutional or other causes, so discoloured, as altogether to lose their infantine and prepossessing character--the permanent incisors appearing cleanly by the contrast. On account of so singular a circumstance occasionally happening, if for no stronger reason, it is imperative therefore, even at the risk of being tedious, to enter minutely into this part of the subject. In colour these teeth are white, because the coating of crusta petrosa which originally invests them is particularly thin, and soon, for the most part, disappears, exposing the enamel; their crowns are shorter, and the neck is well developed, because their fangs are narrow and of less length. In the annexed wood-cut, for the purpose of making the dissimilarity the more conspicuous, a temporary and a permanent incisor are contrasted. _Figure_ 1 is the horse, _Figure_ 2 the milk tooth. The fang of the milk tooth is properly represented of considerable less diameter than the crown; and just where it arises will be observed a little shading, which indicates a sinking in, or nipping up, at that particular spot: the place so narrowed is the neck, which in the temporary teeth of the colt is not badly developed.

However, while the milk tooth is retained in the mouth the neck is not particularly well shown, because the gum encircling the crown in a great measure conceals that part. But the form of the outer surface of the crown can hardly be mistaken. In the foal's tooth it more or less approaches to a semi-circle, from which the permanent teeth greatly differ, as will be seen by comparing the representations of the two as given in the plates. The outer surface likewise is characterized by peculiar indentations: a number of small channels run along it, taking a course from the neck towards the margin of the table, and giving an irregular fluted appearance to the enamel. There will be seen, on the crown of _Figure_ 2, lines intended to convey an idea of the situation and direction of these little grooves. The table is always oblong, but the infundibula are generally absent after the second year, and when they are present, the cavities are narrow, and obviously of little depth. These numerous signs enable the milk tooth to be recognized with facility, at a single glance, for it is seldom that one of the various indications is absent; and after all have been impressed by observation, the milk tooth can hardly be mistaken.

26. _The permanent incisors are indicated by their greater size_, a circumstance which the foregoing wood-cut does not exaggerate. The gum is much further retracted, and this gives to these organs an irregular oblong figure, which is very different from the semi-circular shape of the milk teeth. The incisors, however, are not of equal length in all horses, and in some the gum may be so prominent as to give the permanent somewhat the appearance of a temporary incisor; other indications, however, even then, enable the different nature of each to be with certainty distinguished. The enamel is only partially exposed in the horse tooth; the shaded portion of _Figure_ 1, in the preceding wood-cut, denotes the extent to which it is generally covered during the period of dentition; and when the teeth first appear, the enamel is wholly concealed by a covering of crusta petrosa. That covering is never entirely removed--a small portion of it, even in the oldest mouths, is seen near to the gums. It looks like an accumulation of tartar, and is most conspicuous in the tooth that has been newly cut. The presence or absence of this substance, therefore, should be noted, and moreover, the enamel surface should be further inspected. The numerous channels that give so peculiar a fluted appearance to the milk tooth, are not to be seen upon that of a permanent description; but in the stead are to be detected only one or two broad grooves, which extend the entire length of the crown. _Figure_ 1, at page 48, indicates the shape and direction of the grooves upon the surface of the permanent tooth, though probably a better idea of them is to be derived from an inspection of the coloured engravings, in which they are more prominently exhibited. By means of such guides, the opinion is rendered positive, and the inspection of the table is hardly needed to confirm it; but the table affords corroborative evidence, which may be of service. The table is broader, and the infundibulum is deeper. In this latter cavity, food accumulates in the permanent, but rarely in the temporary incisor. The gum may so contract as to give to the tooth some appearance of possessing a neck, but in reality no such part is developed in the horse incisors, as will be seen by referring to the previous cut, which may, with profit, be compared with the coloured engravings, which depict these members as they are exhibited in the mouth of the living animal.

27. _The temporary cannot be well distinguished from the permanent molars, while the horse is alive._ It is true that the table of the first is somewhat narrower than, though of equal length, with that of the last; but the difference is not so marked as to justify an opinion being pronounced upon the imperfect inspection which, under the most favourable circumstances, can be made of these organs. The number of the molars may, however, be counted, and from this the age of the animal deduced with correctness. The operation can be at all times performed, and the fact ascertained. When, however, removed from the jaw, the character of the molar is easily recognized, for the difference in the length and shape of the fang renders it then impossible to confound the temporary with the permanent tooth.

28. _The various points which denote youth_ must now be noticed. The remarks on this subject, however, must be confined to the mouth, to which this treatise is devoted. In the foal, the membrane of the mouth is of a delicate pink colour, suggestive of its high vascularity. The gums are prominent, for as the permanent are cut posteriorly to the milk incisors, and the germs of the horse teeth are developed even at the time of birth, the anterior part of the jaw is pushed forward to make room for their growth. This gives the little animal somewhat the appearance of being parrot-mouthed, as will be observed by referring to the coloured plate of nine months. Then the palate is low in its position, and the bars appear almost on a level with the tables of the upper teeth, and may even descend beyond them. The lower jaw, also, if felt, will be found to be quite round; and the face, if observed at that part under which the molar teeth are situated, will seem full, or the cheek will look a little blown out. These last signs, more or less, remain till the process of dentition is completed.

29. _The indications of age_ are no less deserving of notice. The edges of the lower jaw become sharp, and ultimately retracted; the cheeks grow flat; the membrane of the mouth loses its vascularity, and puts on a dull yellowish colour; the gums look hard, and the front of the jaw becomes narrower, while at the same time it inclines more backward, causing the teeth to project horizontally. The inclination which age gives to the teeth, will be easily perceived by comparing the coloured engravings with each other; and the peculiarity of the upper and lower incisors not being perceptible at the same time in the mouth of a thirty-years old, entirely springs from the acuteness of the angle which they form at that period. The bars, as years accumulate, also change their positions, being drawn upwards. From the space between the corner incisors and the first molars, the tongue on either side protrudes, as if the narrowed cavity left not sufficient room for the organ to repose in. The extent to which the tongue will project may be conjectured, by regarding the representation of it given in the coloured plate of the thirty-year old mouth. At that age, the protrusion is too strongly marked to escape the observation of any one whose attention has once been directed to the circumstance. Accompanying the inability to retain the tongue within the jaws, is a constant flow of saliva, which continually falls from the mouth of the old horse when the lips be held apart. The latter fact, the author, when he made the drawings for the present work, had ample experience of, as in some instances it occasioned serious delay.

30. _The incisor teeth, in old age_, have their characteristic signs. Mostly they appear unnaturally long, though in rare instances they are worn down almost to the gums. When long, they will generally show interstices dividing them, such interstices, however, not being free, but occupied by a compact mass of foreign matter, derived from the food, and having a black colour. The reader will, by turning to the coloured plates of twenty and thirty years, see these accumulations indicated. When the incisors are very short, they are arranged in a different order to those of the young animal. The tables of the teeth of the young horse, form almost a semi-circle; in the adult animal, they gradually assume a crescentic order, and as age progresses, they ultimately range, more or less, in a straight line. The teeth also look narrower as the fangs descend with the wear of the organs, and in colour they slightly change. The enamel loses much of its semi-opaque and characteristic appearance, assuming a more dull aspect, and a yellowish tint. The crusta petrosa is to be seen only near to the gums, and within the grooves, which often are deep and very well defined, and within which the remains of the once-investing membrane becomes almost black. Then again, the tables themselves change their shape as the years increase. At first, these surfaces are of an oblong and somewhat oval figure; by degrees, however, they become angular, and ultimately more or less square. The continental authors have been very minute, and not a little profuse upon the changes of form which the tables undergo, and attribute the alteration to the gradual wear of the teeth. The correctness of this view they endeavour to establish by sawing a tooth through at various places, and attempting to show, that the forms of the surfaces exposed by this process correspond to the shapes assumed by the table during the progress of age. Their deductions can, in the study, be made to appear true, but in the stable will not bear the absolute application to which these writers would put them. By means of this test, Pessina asserted he would tell the age of a horse, accurately, up to the twenty-second year. The Girards acknowledge the tables will not guide them so far, but nevertheless are willing to apply them during the first seventeen years of the animal's life. I leave the reader to form his own opinion of the value of such speculations--for while I confess they are of some worth as guides to the primary study, and helps to the proper understanding of the cause of those changes of figure to be anticipated--I am not satisfied that any rule drawn from them can be depended upon. For that reason I shall hereafter present the reader with figures of the tables taken from authenticated mouths, rather than amuse him with speculations, which, however imposing they may seem to the ignorant, practice soon discovers to be no more than remote and plausible possibilities.

31. _Some judges depend upon the tushes as indicative of the age_, and taken in conjunction with the other parts they afford corroborative evidence; singly, however, they should not be relied upon, nor should too much weight at any time be placed upon their appearance. In the first place, the tushes are cut irregularly; they may appear in the mouth between the second and third, and they may not pierce the gums so late even as the eighth year; the periods named being of course the extremes. As a general rule, however, they come up between the fourth and fifth year. The custom, however, which Nature so frequently disregards, can afford no positive guide to the judgment, and the wear which may begin thus early or late, should not be too particularly insisted upon. The tushes when they first show are shaped somewhat like a spear head, smooth and rounded on their external surfaces, but grooved on the side which touches the tongue, pointed at their extremities, and sharp at their edges. The inclination of the young tush is oblique, standing forward, and the situation is comparatively near to the incisors. As the animal's age advances, the tushes retract, the grooves on the inner surfaces wear out, and the space which separates them from the incisors increases: all observations, however, concerning the tushes, must be accepted with much allowance, for these teeth are very irregular. As a general rule, the lower tush becomes blunt, or rounded at its point and edges, and also of considerable length, while the upper is often so diminished as to be worn almost to the level of the gum. In stallions, kept only for service, the lower tush, however, frequently attains a great length, presenting the appearance depicted in the coloured engravings of the mouths at twelve and sixteen years. In those plates, the reader will observe the tushes no longer point in a forward direction, but have a decided inclination outward, and somewhat backward also. Another indication of extreme age is also worthy of notice, although, if too absolutely relied upon, it may occasionally mislead. Tartar, not generally found in any quantity upon the other teeth in the horse, accumulates around the tush, and in very old animals almost conceals it. This excessive deposit I have rarely observed in horses of moderate age.

32. _The wolf's teeth or eye teeth aid us in judging of the age_; though we are bound to state of these that they can be received only as presumptive evidence. The wolf's teeth have not been before alluded to, because they are not concerned in mastication, and are no more than the representatives of those organs which form the continuous chain in the mouths of some other animals. These teeth appear to be of no use to the horse. They are little nodules of tooth-like structure, having minute fangs, which are inserted immediately anterior to the first molars of the upper, being rarely seen in the lower jaw, and when present there, always being even yet more diminutive. These wolf's teeth are generally shed with the first temporary molars, and therefore if they can be seen, it may be assumed that the permanent molars have not begun to appear. The assumption, however, must not be converted into an assertion; for in some instances the wolf's teeth are retained, and, in a few heads, will remain after the horse has reached an age far beyond that of colthood: their presence, therefore, rather leads our expectations than confirms our judgment.

33. _The mode in which the horse cuts his teeth_ remains to be pointed out. It is generally said, that the tooth, originally growing in its circumscribed cavity, pushes its way through the parts which oppose its entrance into the mouth. So mechanical an idea is characterized by a small amount of physiological knowledge, and it is time the notions which attributed development to mere force were discarded. The tooth is first a pulpy mass, very soft and highly vascular; the superior part, or that part which primarily shows itself above the gum, is the first to become consolidated. Enamel and ivory are there simultaneously deposited, and gradually these extend towards the fang. When a portion of the fang is completed, and the time has arrived for the tooth to be cut, those structures which oppose the egress of the tooth are absorbed; the absorption taking place, not only on the internal surface, against which the young tooth has been supposed to exert its force, but also upon the external parts, upon which it could have no effect. By absorption the barrier is removed and the tooth then comes forward. The process is very beautiful, and no less worthy of admiration is the manner in which the milk teeth are shed. The incisors lose their fangs, and just when the permanent teeth appear, the crown of the temporary ones is removed from the mouth. The removal of the fangs of the milk incisors is the result also of absorption, and the same process effects the removal of the temporary molars, only its operation is not precisely similar; for in these last, not only the fang but the greater portion of the crown is taken away, and little more than the table is cast off when the remnant of what once was a tooth is at length shed. The process of cutting the molar teeth will be more clearly comprehended by referring to the annexed wood-cut, in which the darkened spots indicated by the line running from _a_ denotes the permanent tooth already through the gum and in the mouth, though still covered and partially concealed by the retained table of the temporary grinder _c_. The appearance of the table of the temporary molar when cast off is shown in the figure immediately underneath, to which the letter _c_ is also affixed, and the projecting portions ascending from its edges exhibit the last remnants of what originally was the fang: _b b_ are molars, well up and worn to a level.

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.

[Footnote *: 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.

38. _At nine months old, the corner milk teeth are up, but their edges do not yet meet._ The coloured engraving will show the appearance they present, and likewise exhibit the protruded state of the gums at this age. The drawing was made from a head in the author's possession. It has been tested several times, and its correctness fully ascertained. The last occasion, when it was authenticated, was by the mouth of a bay colt, by Muley Moloch, out of Canaletti's dam, with which it perfectly agreed.

_The Corner Milk-teeth up, but their edges do not yet meet._]

_A full Mouth of Milk Incisors, all of which show considerable wear._]

39. _At one year_, all the temporary teeth are up and in apposition; but by this time two pairs of permanent teeth, which are the fourth molars, have made their appearance, and the yearling therefore has sixteen molars and twelve incisors, or twenty-eight teeth. The large number of yearlings annually brought into the market afford such frequent opportunities of examining the mouth at this age, that I need not state here the means by which the drawing has been authenticated. It would be a task of supererrogation to allude further to a fact which is so well known and thoroughly established.

40. _At eighteen months_, the incisors show some wear, the infundibula look as if they would soon be obliterated; indeed some of them may be lost. At or about this time also four more permanent molars, one on each side of either jaw, being the fifth in situation, protrude into the mouth.

41. _At two years old, there is a full mouth of milk incisors, all of which show considerable wear._ The coloured engraving of the two-year old mouth, will convey an accurate idea of the features which it presents at that age. The original drawing was made for the Jockey Club in anticipation of the celebrated Running Rein trial. Accepted by such authority, it perhaps hardly requires further proof of its correctness, but it has since been repeatedly tested. On the last occasion it was compared with the mouth of a chesnut filly, by Calmuck out of Miss Greatrex, and was found to agree with the indication therein presented. At two years, the infundibula are lost in the temporary incisors, and the fifth molars are in perfect apposition; indeed the smooth surfaces of these last are the best evidence that the animal is two years old, for he cannot then be far below that age. The incisors having been for some time employed, but still being to be retained for some months, have an aspect of wear and strength conjoined. The two-year old mouth, therefore, by those who cannot distinguish the milk from the horse teeth, (none of the latter being present to help the judgment by the contrast they exhibit) is likely to be mistaken for that of a five-year old; especially if the colt chances to be somewhat fully developed. A regular horseman, however, would not require the aid of the mouth to discover the animal was still in its colthood.

42. _At three years old, the centre horse teeth are well up, and are distinguished by their size, shape, and colour._ The appearance which the mouth will exhibit, the coloured engraving represents. The original drawing is in the possession of the Jockey Club, for whom it was made. It has, however, been repeatedly tested, in order to place its correctness beyond doubt. Both colts and fillies have been inspected for this purpose, and equally have the different breeds been consulted. As the public, however, place the greater confidence in blood stock, it may here be mentioned that the appearances perfectly coincided with those exhibited by a brown colt by Muley Moloch out of Miss Greatrex, and Roxey, a brown filly, by Lanercost, out of Ellen Percy, besides various others which it would be both needless and tedious to recapitulate. The mouth, at this period, indeed is so marked, and in general so regular, that it is the more readily recognized. The new horse incisors, by their size, contrast with the milk teeth which are still retained. The comparative length and squareness of their figure cannot fail to attract attention, and their deeper colour can hardly be unobserved; that colour is caused by much of the primitive coating of crusta petrosa being retained, or only removed from the edges where the enamel is bright. But as a vast number of horses are sold at this age, and many are started for heavy stakes, it will be imperative now to proceed more cautiously in the description. About this time the terms "rising three," or "coming three," or "three next birth-day," are made use of, as well as "three off"--the first phrases indicating that the colt is yet between its second and third year, or will in a month or more be three years old, and the last term meaning that the animal has attained its third year, and has recently entered the fourth year of its existence. The season here materially aids the judgment; for if a blood horse shows a fair three-year old mouth in December, it is unhesitatingly pronounced to be "coming three;" and if it exhibits the same appearance in January the animal is declared to be "three off." The same holds good with the coarser breeds, only, as before stated, the month of April would then be estimated as that of December in the former case, and May would answer to January. "Coming three," however, can, with a little stretching of the term, be applied to any foal; and is commonly used when the colt is strictly but "two off;" for the terms are somewhat loosely used, though in their stringent sense a horse is only rising three, four, or five, after the mouth has began to assume the form which characterizes the respective ages. When the colt is two off, that is two years and three months old, the milk teeth are all retained, and to a casual observer, the mouth would still say "two." A little closer observation will, however, correct the judgment, for looking attentively, perhaps a slight, and only a slight difference in the colour of the central incisors may be remarked. The tinting of the enamel may be a "thought" darker, and yet the contrast so delicate, that the difference can only be seen in a certain light. Then again casting the eye to the gums of the upper central incisors which are first shed, that part of them immediately covering the neck of one of these teeth may show a little redness, and the other exhibit nothing of the kind. The redness indicates that nature is making ready for the appearance of the permanent incisors, and on evidence no heavier than this, the animal is pronounced to be "two off." The redness, it may be said, can be artificially produced--so it may be, but the natural character can hardly be imitated. The colour in the normal mouth is not deep or angry; it is not caused by inflammation, but is only increased vascularity of the part, and it is at first limited to the edge of the gum. The colt shows no symptoms of tenderness in the reddened gum, but stands quite as still, and even more quiet when it is pressed, than when the opposite one is handled. If the part had been tampered with, the animal would probably tell tales when the finger touched it, and the redness would be more intense on the prominent or bulging portion of the gum than where the margin encircles the neck of the tooth; while it is ten to one inflammation had been produced rather than vascularity excited. Little occasion, therefore, is there to fear imposition, and little room for those who would practise it to hope for success. The next indication of advancing age is given by the gums growing more vascular, even now looking inflamed, while a yellow deposit (the nature of which is not well understood) may be seen upon the neck of the tooth, and the central incisors of the upper jaw, if felt, may probably be found loose. In another or about the sixth month, one of the central incisors is removed. It does not fall out, as is generally stated, but while the animal is feeding, the tooth is, as by accident, wrenched off. The gum bleeds, and being slightly lacerated, looks sore and angry for some time. The sharp edge of the new brown-coated permanent incisor is now seen protruding. In a week or two the remaining milk central incisor of the upper jaw is, by a seeming accident, forced out; and the mouth now has an irregular appearance, the edges of the upper central incisors not being level with the tables of the lateral milk teeth. The lower central incisors, when the upper milk teeth are lost, generally are loose, and their gums inflamed; but a month or sometimes six weeks may elapse before these are gone: by that time the upper permanent teeth have grown considerably. When the central milk incisors have disappeared, the molars begin to change, and those of the upper jaw are the first uncovered; not in any regular order, or the two teeth on the same day, but generally the first molar before the second, the wolf's teeth mostly departing at the same time. A week or two subsequent, the first two permanent molars of the lower jaw are laid bare, so that at or about the ninth month, the horse has all those teeth, which denote the animal to be three years old, fairly in the mouth; that is, he has between the second and third year cut four horse incisors and eight permanent molars. Lest the description should not be perfectly clear, or such as to enable the reader to readily understand which teeth by this time are shed, a drawing of the head of an adult animal, which forms the frontispiece of this work, was designed. It will enable the reader to form some notion of the extent of the horse's mouth and likewise of the positions of the teeth. Near to the teeth will be seen figures which do not denote the periods when these organs first appear, but the time at which they are fairly up, or to some extent exhibit wear. In that engraving no further notice is taken of the milk teeth than is conveyed by the small star associated with such of the figures as indicate the places from which they have been displaced: thus the figures 1, 2, and the last 4, having no star, indicate that those molars are developed only as permanent teeth. The figures 3*, 3*, 3*, having stars, denote that milk teeth originally occupied the situations where these teeth are shown: those figures will be seen above and below the central incisors and the first two molars of either jaw; and as but one side of the face could be displayed, of course the number has to be doubled, the colt getting twelve additional permanent teeth by the time it completes the third year. At three years, therefore, the central permanent nippers are in apposition, and show wear, though to only a limited extent. The infundibulum is broad, as depicted in the accompanying cut.

In the above representation of the table of a three year old tooth, it will be remarked that the infundibulum appears in the outward direction to extend quite across the surface. This aspect is produced by an indentation at that part, which, by the completion of the third year, is in most instances not worn out, but after the third year is attained, it speedily disappears; so the table of the three year off has become somewhat broader, and the infundibulum circumscribed, or well defined, as it is shown in the subjoined wood-cut.