22 Surgical Diseases and Surgery of the Dog 



eptic applications are indicated, and later inunctions, as the inflam- 

 mation subsides. 



WOUNDS. 



A wound is a traumatic or surgical lesion involving a breach of 

 surface continuity. A wound is said to be simple when it has a clean 

 edge and contains no foreign body ; it is said to be complicated when 

 it gives lodgment to a foreign body or has been exposed to infection. 

 The local phenomena of wounds are pain, hemorrhage and loss of 

 function, of degree depending upon the extent of injury. Division 

 of a large or important vessel may be followed quickly by death, and 

 severe hemorrhage may terminate in death some hours later by in- 

 ducing cerebral anemia and consequent depression of the vital nerve 

 centers. Division of a motor nerve results in limited paralysis, 

 while the severing of a tendon causes at least temporary functional 

 impotency. An ever possible constitutional phenomenon is reflex 

 shock, which, however, is rare. The result of infection may be 

 abscess, erysipelas, septicemia, or pyemia, but wounds that have com- 

 menced to granulate are proof against infection, the granulating 

 tissue forming a protective barrier. This has been demonstrated by 

 Billroth's well-known experiment of binding up a wound in such 

 condition with a fetid bandage without any reaction following. The 

 occasional more remote effects are thrombosis and embolism, and 

 entry of aii- into the veins. Amussat made experimental wounds in 

 the veins of the breast in numerous dogs into which air entered 

 spontaneously, the animals dying in from one to twenty-seven min- 

 utes thereafter, while Erichsen found that the entry of a cubic inch 

 of air would not cause death. 



Wounds are usually classified according to their character, viz, 

 incised, punctured, contused, bite, gun-shot, and poisoned. 



Incised wounds are produced by sharp instruments and are 

 usually simple, free of complications, and heal kindly without leav- 

 ing much scar, though they may give rise to considerable hemorr- 

 hage and complete temporary functional impotency of a part when 

 tendons or nerves are severed. Punctured wounds are caused by 

 penetrating sharp bodies, hooks, etc. Such bodies may break ofif, 

 the extremity remaining within the wound. If aseptic, it becomes 

 encapsulated, but if septic gives rise to purulent inflammation. As a 



