SEBACEOUS CYSTS, 241 
hood they should be opened as early as possible and properly dressed. 
Free incision and drainage are sometimes useful. Thermo-cautery will 
arrest the hemorrhage and prevent auto-inoculations. (See Adscess.) 
Sometimes a general treatment is required. Purgatives and arsenic 
seem of little advantage. Cresyl and naphtol are good in some cases. 
VII. 
SEBACEOUS CYSTS. 
These are seen with varying frequency in all domestic animals and on 
any region of the body. In horses they are most frequent on the nose, 
in the false nostril, the lips, the ear and the sheath. Their origin is still 
in doubt; the majority of authors say that they are due to the accumula- 
tion in sebaceous glands of the product of their secretion; but one may 
exceptionally observe them on the buccal mucous membrane and on that 
of the lips, where there are no sebaceous glands: perhaps these are cases 
of epidermic occlusions. The first cause is the obliteration of the orifice 
of the duct common to the hair and the sebaceous follicles, produced 
either by dried epidermic scales or by inflammation. The size varies 
from that of a hazel-nut to a large nut. They are round, perhaps a little 
flattened, depressed in the center, well defined in their surroundings, 
painless, of various consistency, most commonly puffy, more or less _resis- 
tent, at times fluctuating or again of an uneven consistency, very hard 
in some places, very soft in others. The contents, formed of epidermic 
cells and greasy substances, vary ‘in their aspect according to the pro- 
portion of the constituent elements; generally it is a caseous mass, at times 
a solid substance analogous to solidified fat (steatomatous cyst), at others 
it is a matter looking like honey (melicerous cyst). 
If the positive diagnosis in some cases is quite difficult, it is of 
secondary importance: the sebaceous cyst cannot be mistaken only for 
affections requiring the same mode of treatment—puncture or removal. 
Simple puncture is always insufficient ; it permits the evacuation of the 
contents, but the wound heals rapidly and the growth returns. Repeated 
punctures followed by irritating injections (tincture of iodine 1-3, chloride 
of zinc 1-10) are often sufficient to obtain recovery. We succeeded 
with this treatment in the case of two large cysts of the false nostril. 
Potential caustics used after the evacuation of the contents are also 
somewhat successful. Ablation is the best way, however. After incision 
of the skin the mass is enucleated with the bistoury or the director, care- 
fully avoiding the opening of the sac. With antiseptic care the cicatriza- 
tion of the wound is rapidly obtained. 
16 
