218 
ON DISEASES OF THE DENTAL APPARATUS 
When it is the first superior molar that is deficient, then is 
manifested a very curious phenomenon. In this case, in fact, the 
anterior molar of the inferior jaw, obeying the laws of its inde- 
finite growth, elevates itself and passes the level of the neigh- 
bouring tooth. It then acts upon the palatine vault like a battering 
ram, striking continually against the roof of the mouth in the alter- 
nate motions of right and left made by the jaw in mastication. Its 
reiterated and powerful contusions furrow along the thickness of 
the bone, which it finally perforates, and a hole is made resem- 
bling that made by a projectile body through a body resistant. 
“ I have had,” says Solleysel, “ a mule which had one of the 
grinders of the under jaw of an extreme length. As the tooth 
above had fallen out, the one below mounted into this void, and 
pierced the palate of the thickness of a finger, a thing which 
caused him a great difficulty when he drank. I have brought 
forward this example as extraordinary, and to shew that the teeth 
when once the borders pass each other, and that they are not 
used one upon the other in masticating, increase extremely, until 
they pierce the palate, as I have said.” 
4. Caries of the Teeth . — The molar teeth of the horse are more 
frequently than is generally admitted or supposed attacked with 
a profound alteration of their substance, which has been called 
caries, although, nevertheless, there may not be a perfect analogy 
between this affection and that similarly named when situated in 
the bones. 
Caries of the bones implies an active labour in which the 
vascular apparatus plays an important part. It is a phenomenon 
of interstitial suppuration under the influence of the inflammation 
which has set in play the capillary system of the organ. In order 
to explain the caries in the teeth we cannot invoke inflammation 
and the modifications which it induces in the tissues which it 
attacks ; nor to say that inflammation implies an active circulatory 
movement, an afflux of liquid, an alteration, nervous, &c. Now, 
in the teeth we know that there are neither nerves nor vessels : if 
they are living, the laws which preside over their vitality are 
entirely unknown to us ; how, then, penetrate into the secrets of 
the alterations which they experience, when the conditions of 
their normal existence are still enveloped in such obscurity ? 
Neither is it possible to resolve the question as to the essence of 
the affection designated by the name of caries. 
We are about to make known only the different modes of ex- 
pression relative to it. 
The caries of the teeth seems to attack in preference the hoarly- 
like substance. Under 'its influence the ivory takes on a dark 
brownish or blackish colour, and disseminates a stinking odour, 
