42 
ALVEOLAR PERIOSTITIS. 
the dog it stands out clearly on the shining white surface of the tooth, 
Hertwig states that in goats tartar sometimes appears black and metallic 
from admixture of oxide of iron. 
The deposit spreading may completely encapsule the crown above ; 
while, as it increases below, it produces atrophy and necrosis of the gum. 
Here lies the chief danger. As soon as the alveolus is laid bare, it 
becomes inflamed by the fluids of the mouth. This is by far the 
commonest cause of alveolar periostitis in dogs, and is especially frequent 
in house dogs. 
The food decomposes in the alveolus, producing a grey slimy material 
which can be partly squeezed out by pressure, and has a peculiarly pene- 
tiating odour. The gum is bluish-red and swollen, bleeds easily, and is 
sometimes studded with little abscesses. The disease has hence been 
named “scurvy,” whilst, on account of the offensive smell, it is also 
known as “mouth rot.” 
The black coloration, produced by feeding on husks and brewers’ grains, 
must not be confounded with tartar. Its exact nature is not yet known, 
but it affects only the surface of the crown. The significance of tartar 
lies in the possibility of its exciting alveolar disease. Provided the alveolus 
is healthy, recovery follows removal of the deposit; but teeth already 
much loosened can only be extracted. The smell is often so offensive 
that the dog cannot be tolerated in the house. 
Treatment. I he deposit is removed with teeth scalers or similar 
instruments (fig. 18), avoiding injury of the gum or alveolus. To get 
lid of the incrustation, the teeth may be regularly cleansed for some time 
with pumice. Sporting dogs being the usual patients, these measures 
can be carried out thoroughly. The gum is protected by placing the 
instrument close to it, and working towards the top of the tooth. 
Immediately the tooth becomes loose, extraction is the only resource. 
(I)) DISEASES OF THE ALVEOLI. 
(a) alveolar periostitis (periostitis alveolaris). 
This is by far the commonest dental disease of herbivora and carnivora, 
and especially of dogs. As its development, appearance, and causes vary 
considerably in different classes of animals, it is advisable to study it 
separately in each class. 
(a) Inflammation of the Alveolar Periosteum in Herbivora . 
The roots of the teeth are fixed in the alveoli by the alveolar perios¬ 
teum or alveolar dental membrane. The outer layer of the periosteum 
