BUENS AND SCALDS. 37 



during the splint treatment of fracture of the bones of the leg. 

 In this instance the thin amount of soft tissue covering the heel 

 is compressed between the os calcis and the splint, and therefore 

 dies. The same process may occur on the back of the forearm or 

 wrist from splint pressure. 



The spreading gangrene due to infectious processes may be 

 classified with that due to capillary obstruction, although the direct 

 action of toxins on the tissues also plays a part in its production. 

 Such gangrene tends to spread by virtue of its cause, and does 

 not show halting places determined by vascular arrangements 

 such as have already been described when dealing with gangrene 

 due to occlusion of arterial trunks. 



In states of obstructed or much enfeebled circulation, microbic 

 invasion of tissues may occur and lead to necrotic or gangrenous 

 processes. These processes are common in strangulated gut, 

 and may also be seen in the mucous membrane of the mouth, and 

 as the result of slight injuries of the integument of the extremities 

 in old people. 



BUENS AND SCALDS. 



In burns of the third degree where there is partial destruction 

 of the true skin, the nerve endings are exposed, and consequently 

 great pain is induced. 



Burns involving the surface of the trunk are more dangerous 

 than those of the limbs, possibly because of the irritation of 

 nerve terminations which are in close connection with important 

 centres. 



Parts which are insensitive from lesions of the sensory nerves, 

 or in a patient still unconscious from the administration of an 

 anaesthetic, are very liable to be burnt from the too close applica- 

 tion of hot water bottles, and this is peculiarly prone to happen 

 in the lower extremity. 



It is doubtful whether ulceration of the first part of the 

 duodenum is at all a frequent complication of extensive burns, 

 even those of the trunk, when the case is kept free from septic 



