DERMATITIS. 233 
Gangrenous dermatitis has a complex etiology. It is frequently the 
termination of severe cutaneous, traumatic, toxic or infectious phlegmasias 
which have not been controlled. Solar erythema, feeding on damaged 
food altered with fungi, may promote it (Friedberger and Frdhner). 
Gangrenous dermatitis of extremities—cutaneous quittor—so frequent in 
horses during winter, is due especially to the action of cold (freezing) mud 
on the skin Irritating liquids (urine), caustics, traumatisms and especi- 
ally blows that animals give to themselves may bring on the same result. 
The swelling of the hind extremities predispose to this affection (Chenier). 
As soon as the integrity of the skin is destroyed, the action of the bacteria, 
added to that of the other pathogenous causes, increases the inflammatory 
process and brings on gangrene. 
The diffused tumefaction and soreness of the region, the bristling of the 
hair, the oozing of the skin, the dark coloration of the diseased parts 
when free from pigment, all indicate the severity of the phlegmasia and 
the threatening gangrene. In cases of cutaneous quittor, the inferior part 
of the leg is tumefied more or less and the swelling extends at times above 
the knee or the hock. The sensibility and the lameness are more or less 
pronounced according to the degree of inflammation. On the inflamed 
part there soon appear “small elevations which spread open and allow 
the sloughing of necrosed pieces mixed with pus and blood” (Barthe), 
or moist cutaneous patches partly mortified or already gangrenous. It is 
not rare to detect in the centers of these patches deep fluctuation, indicat- 
ing the existence of subcutaneous suppuration. 
The preventive treatment depends upon the etiology. At times the 
feed has to be changed (solar erythema), or again, the numerous causes 
of irritation upon the skin must be prevented or attenuated. For cut- 
aneous quittor especially, the hair of the lower parts of the extremities 
should not be dressed (clipped) during cold or rainy weather (Weber), 
and the legs should be carefully attended to (tepid washing, drying, appli- 
cation of an isolating, greasy substance, in cases of work in freezing mud). 
Swollen, elephantiasic legs, whose tissues are predisposed to necrosis, re- 
quire special attention. (See Frost-bites.) 
Against incipient dermatitis, the means indicated in the chapter on 
Inflammation should be used. Friedberger and Fréhner recommend an 
ointment of lead and tannin, or antiseptic vaselines. We generally use 
antiseptic baths twice a day, with bandages wet in the same fluid. Scari- 
Several years ago we saw a true epizooty of this affection among the 
horses of the railroad companies in New Vork, caused by the free use of salt to 
melt the snow in the streets. We have seen animals in which the entire 
skin had sloughed on the whole inside of the legs from the feet up to the 
groin ; others where the entire abdominal wall was bare of skin, 
