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.
[Illustration]
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_.
[Illustration]
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.
[Illustration: _NINE MONTHS OLD._
_The Corner Milk-teeth up, but their edges do not yet meet._]
[Illustration: _TWO YEARS OLD._
_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.