304 PEINCIPLES OP VETEBINAEY SUBGEET 



ous tissue from witliin— that is, following injuries to the par- 

 enchyma of the lung, perforation of the esophagus, rupture of 

 the rectum. When air or gases accumulate in the cavities of 

 the body, as the thorax (by perforating chest wounds), it is 

 termed pneumothorax; or, when accumulating in the rumen 

 of a cow, stomach or intestines of other animals, it is termed 

 tympanitis and of surgical interest, as the trocar and canula 

 may be called into play to relieve the bloated state. 



What are the symptoms of emphysema ? 



A more or less diffused swelling, painless, of normal tem- 

 perature, producing a fine, crackling sensation when stroked 

 with the hand, and tympanitic on percussion. 



What is the prognosis of subcutaneous emphysema 9 



Favorable, unless it is a symptom of serious destruction: 

 of vital tissues. 



What becomes of the air in the subcutaneous tissue ? 



It is gradually absorbed by the lymph and blood vessels. 

 W hat is septic emphysema ? 



The accumulation of putrefactive gases, the product of 

 gas-producing bacteria, in the subcutis. 



W hat is the etiology of septic emphysema ? 



Bacteria capable of manufacturing putrefactive gases in- 

 vade the subcutaneous tissue. There is therefore a marked dif- 

 ference between traumatic emphysema, where air pure and 

 simple is contained in the tissues, and septic emphysema, 

 where the tissues contain gases of putrefaction, as hydrogen, 

 sulphuretted hydrogen, carbonic acid, etc. 



What are the symptoms of septic emphysema ? 



The presence of these putrefactive micro-organisms not 



