SA'IN DISEASES. 287 



or the absorption of putrid matters from a sore or other 

 diseased surface. Sheep, horses, and swine fed on green or 

 even harvested buckwheat are Hable, and all animals kept in 

 close, filthy, unhealthy places, or in the vicinity of accumula- 

 tions of decomposing animal and vegetable matters. Sudden 

 suppression of an habitual discharge, heating food, and new 

 grain and forage are occasional causes. But probably all of 

 ihese 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., burns, scalds, wounds, dropsies of the 

 limbs, and, above all, the keeping of patients with open sores 

 where there is excessive emanation from decomposing organic 

 (especially animal) matter, or the dressing of erysipelatous and 

 healthy sores with the same sponges. 



Syinftoms. — There is usually a preliminary fever, loss of 

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

 breathing, constipation, high-coloured, scanty urine, and eleva- 

 tion of the temperature of the rectum, soon followed by a 

 diffuse, hot, tender, shining, itching swelling, spreading 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 swelling will be greater, according 

 as the inflammation involves the skin only, extends to the con- 

 nective tissue beneath (phlegmonous), or is complicated by a 

 liquid exudation (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. The inflamed skin is tense 



