WOUNDS AND THEIB TREATMENT. 303 



the endothelium, and if from any diseased condition the endothe- 

 lium is changed, or if the blood runs off through another opening, 

 or if the circulation is obstructed by a ligature, the blood becomes 

 coagulated, and we quickly have the formation of a thrombus. 

 This not only closes the bloodvessel externally, but it is more or 

 less extended into the bloodvessel until it reaches the first branch 

 where there is an active current of the blood. These useless ves- 

 sels soon become converted into solid cellular connective tissue. 

 We shall refer later to the puriform, pussy, and purulent degen- 

 eration of the thrombus. 



It is readily understood that the formation of a thrombus may 

 occur rapidly when the ends of bloodvessels which have been 

 detached have their opening reduced by contraction or twisting 

 of the coats (media and intima), as in the case of crushing or lacer- 

 ating, especially in the capillaries or small veins. In partial injuries 

 of the bloodvessels the bleeding may be stopped without com- 

 plete obstruction of the bloodvessel. In favorable conditions the 

 lacerated wall of the bloodvessel becomes coated with a solid 

 coagula. This becomes organic, so that the only result is a 

 slight thickening of the wall. 



The pain of a wound is indicated in the dog by howling and 

 crying when the injury occurs, or later when the wound is exam- 

 ined. The pain evinced by the patient also depends upon the 

 individuality of the animal. Some dogs are great cowards and 

 show great sensitiveness to the slightest pain, while others will 

 stand any amount of it; and we must, therefore, always carefully 

 examine a wound, seeing its depth, situation, and character, and 

 not in any way be guided in making a diagnosis by the symptom 

 of pain indicated by an affected animal. Wounds of the lips, 

 lower extremities, external genitals, and of the bones are the most 

 painful. In the dog we see occasionally a series of symptoms 

 which are identical with what is known in man as "shock." This, 

 as a rule, occurs immediately after any painful injury, such as 

 extensive crushing of tissues or bone, and during or after operatiotis. 

 The visible mucous membranes in the skin become pale, then cold; 

 the eyes are fixed, the pupils dilated; the pulse becomes irregular, 

 reduced in volume; and the respiration weak and irregular. The 

 animal appears indifferent or unconscious. These symptoms may 

 disappear very rapidly or in some cases go on until the animal 



