752 
FRANK H. MILLER. 
portion of the peri-dental membrane is called which lies near 
and surrounds the neck of the tooth and fixes it to the alveolar 
rim. The same conditions which were instrumental in cansing 
the precipitation of tartar having evidently much lowered the 
vitality and resisting powers of the alveolar tissues, pathogenic 
and other micro-organisms with which the month normally is 
infected, even in health, find here suitable conditions for their 
growth, and as a result the alveola soon becomes bathed in pus 
and the structures therein, which not only supported the tooth 
but bear direct relation to the nourishment of certain parts of 
the same, fade away and leave in their stead only detritus, with¬ 
in which remains a loose and denuded tooth, held in situ per¬ 
haps by the extreme end of its root or roots, and very imperfectly 
nourished by the blood which may still pass into the foramina 
of the same. Such teeth as are lost through this process of de¬ 
cay fortunately do not give the animal that amount of anguish 
or odontalgia as comes to ourselves by reason of caries penetrat¬ 
ing through the crown and exposing the pulp in all its compar¬ 
ative health and sensibility to external influences. 
The whole history and close observation of such patients 
would indicate that the changes are truly atrophic in their na- 
ture, and that the gradually diminishing vitality of the peri¬ 
dental membranes in all these cases brings about early changes 
in the nerves of sensation whereby the disease progresses to its 
end, or the loss of the tooth, in a more or less painless manner 
as compared with the changes incidental to loss by true caries. 
In treatment of such cases as have several teeth already 
deeply involved, I think extraction the proper course to follow, 
since usually the value of the patient will scarcely warrant the 
outlay of the long continued treatment, which will be at best 
not particularly certain of success in the end, and especially if 
the animal be aged. When it is imperative that several teeth 
be removed, I invariably use sulphuric ether anaesthesia, regard¬ 
less of age or condition, and consider it absolutely safe if pushed 
rapidly to completion and withdrawn immediately when that 
condition is produced, which will, generally speaking, suffice for 
