DISEASES OF THE SKIN 295' 



Burns and Scalds. 



WJiat is a burn ? 



The destruction of the skin and underlying tissues due to> 

 an exposure to excessive temperatures. 



What are the causes of burns and scalds ? 

 Fire, caustics, steam, hot water, etc. 



Under what circumstances are burns of therapeutic value ? 



When employed as the actual cautery, also when chemi- 

 cals are used as rubefacients, vesicants and escharotics. 

 Wliat points does the surgeon take into consideration in 

 burns ? 



' The intensity and the extent of the hurn. 



Depending on the intensity of a burn, which three degrees are 

 of practical value f 



First degree : An excessive temperature acts but momen- 

 tarily, followed by dilatation of the bloodvessels, especially" 

 the arteries ; consequently the skin not provided with pig- 

 ment appears bright red (erythema) ; at the same time there 

 is more or less pain and some swelling due to serous infiltra- 

 tion of the skin. These symptoms disappear in a few hours, 

 but are followed by desquamation of the epidermis. 



■ Second degree : An excessive temperature acts a little- - 

 longer than in the first degree. As the result of this a serous 

 Bxndate accumulates under the horny layer of the skin, rais- 

 ing it ; in other words, producing larger and smaller blisters. 

 These blisters are not very well seen in animals with a hairy 

 Boat, as the hair, being firmly fixed in the cutis, holds the 

 apidermis down. The swelling and pain are considerable. . 

 The pain disappears in about twelve to twenty-four hours,.^ 



