’ NECROSIS. 461 
tegumentary covering and cut deeply into the phalanx. It has been rec- 
ommended to limit the scraping of the carious part inside the limits of 
its extent, and to complete the operation by the application, on the dis- 
eased part, of a small wadded tent impregnated with caustic fluid, such. 
as sulphuric acid diluted to the third or the quarter. These caustic solu- 
cae tions were supposed to have the great power of limiting their action to. 
~ the extent of the altered structures. We have already stated how erroneous . 
aed . this belief is. It is better to be done with the caries at once, to scrape 
down to healthy tissue and apply an antiseptic dressing. In cases of 
caries of the third phalanx, when, exceptionally, the podophyllous and 
velvety tissues are sound, they must be respected: their preservation is. 
of the utmost importance for the repair of the new hoof. In such in- 
stances, the fragments of the membrane corresponding to the caries must 
be carefully dissected to expose the diseased bone (Bouley). In other cir- 
cumstances, the periosteum must be carefully saved. It should be sepa- 
rated carefully from the bone, so as to preserve it and have it co-operate in 
the formation of new bone. Upon the saving of the internal cellular layer 
of the periosteum depends, indeed, the regeneration more or less‘rapid and 
perfect of the destroyed bone; daily practice in human surgery proves it 
sufficiently. Very extensive alterations may necessitate amputation in 
small animals. The special rules of the treatment of caries in some regions. . 
are indicated in the chapters relating to those affections. (See Vol. II.) 
The general indications, so important in the caries of man, are, however, 
secondary to all animals. Yet in dogs there are cases where it is ad— 
vantageous to administer cod: liver oil, quinine, Fowler solution or alka- 
lines. 
VI. 
NECROSIS. 
Necrosis, ary caries, dry gangrene of bones has a complicated etiology. . 
In animals traumatism is a great producing cause. Bones of the extrem- 
itiesare, on that account, most exposed ; the radius and the tibia are those - 
~ where it is generally observed, by the fact of the frequency of the con— 
tusions to which they are exposed and their want of protection on their 
"internal face ; phalanges, scapula, sternum, maxillary, offer also frequent 
examples. 
Several diseases, distemper among them, are sometimes accompanied with 
1 An unusual case of necrosis of the dorsal vertebre is reported by F. Allen, D. V.S., 
which gave rise to progressive paraplegia in an old horse, which ended fatally, and at. 
‘the post-mortem of which the annular portion of the 7th, 8th, 9th and roth dorsal. 
vertebra: were more or less necrosed.—Amer. Vet. Review, vol. 8, page 360. 
