Skin Diseases. 287 



matters from a sore or other diseased surface. Sheep, 

 horses and swine fed on green or even harvested buck- 

 wheat are liable,, and all animals kept in close, filthy, 

 unhealthy places or ia the vicinity of accumulations oi 

 decomposing animal and vegetable matters. Sudden sup- 

 pression of an habitual discharge, heating food, and new 

 grain and forage are occasional causes. But probably all 

 of these do little more than lay the system open to the 

 attack which would otherwise be escaped. More direct or 

 exciting causes we find in local irritation, — as exposure to 

 a hot sun (newly-shorn sheep), chafing inside the elbows 

 or thighs, the presence of rancid fats on the skin, injuries 

 from the harness, bites of insects, etc., bums, scalds, 

 wounds, dropsies of the limbs, and above all the keeping 

 of patients with open sores where there is excessive ema- 

 nation from decomposing organic (especially animal) 

 matter, or the dressing of erysipelatous and healthy sores 

 with the same sponges. 



Symptoms. There is usually a prehminary fever, loss of 

 spirit and appetite, heat of the skin, accelerated pulse and 

 breathing, constipation, high-colored, scanty urine, and 

 elevation of the temperature of the rectum, soon followed 

 by a diffuse, hot, tender, shining, itching swelling, spread- 

 ing from a wound or other seat of irritation or even on a 

 previously healthy skin. In white skins the redness is 

 very deep, the shade being darker according to the gravity 

 of the case, and disappearing under the pressure of the 

 finger only to reappear quickly on its removal. The 

 swelliug will be greater, according as the inflammation 

 involves the skin only, extends to the connective tissue 

 beneath (phlegmonous), or is complicated by a liquid exu- 

 dation (oedematous). It shows a tendency to wide and 

 rapid diffusion over the skin, its advancing border being 

 always abruptly elevated from the healthy integument, 

 though at points where it is recovering it may subside 

 gradually and insensibly to the healthy surface. Tlia 

 inflamed skin is tense and smooth, but pits on pressure, 



