PRINCIPLES OF VETERINARY SURGERY 315 



effusion. The dog and the other small animals are less ex- 

 posed to such injuries. 



The physiognomy is variable. The symptoms by which 

 they are recognized may be either grave or trivial, accord- 

 ing to the region attacked and the importance of the organs 

 affected. Human surgeons, first, Boyer, and then Dupuy- 

 tren, have designated different degrees of contusion, from 

 which the following, purely conventional classification ema- 

 nates : ( I ) A first degree contusion, or simple bruise of the 

 skin consisting of ecchymosis due to the rupture of its cap- 

 illaries ; (2) a second degree contusion in which large blood 

 vessels have been ruptured and a sanguinary tumor has re- 

 sulted ; (3) a third degree contusion in which there is crush- 

 ing of the subcutaneous tissues, disturbances and mortifica- 

 tion of the anatomical elements, fatal gangrene of the af- 

 fected structures, and frequently synovial and serous ef- 

 fusions. 



Briefly considered these three A'arieties of contusions 

 demand the following description : 



I. Contusions of the First Degree. — Ecchymosis of the 

 skin. — The character of first degree contusions depends much 

 upon the preservative vitality of the part afflicted. The ana- 

 tomical elements have only been disorganized, — separated. 

 The traumatism has not been forcible enough to cause morti- 

 fication of the entire focus ; only a few cellular elements are 

 destroyed, and these become isolated by the infiltration of 

 blood or serum. The ecchymosis is manifested by a diffused, 

 reddened area easily seen on an unpigmented skin. It is ac- 

 companied by a stinging and benumbing pain When the 

 blow is violent and affects a limb, the pain may be sufficient 

 to cause lameness, and a pronounced oedema may soon ap- 

 pear as a consequence of the resulting vaso-motor paraly- 

 sis. In the domestic animals, with the exception of the hog, 

 oedema is often the only indication that a contusion exists. 



