': CONTUSIONS 49 



toma. As a result of the proliferation of the fixed tissue cells 

 about the peripheral neighborhood of the hematoma, a cellu- 

 lar infiltration with subsequent formation of fibrillar connec- 

 tive tissue forms, eventually replacing the extravasation 

 (this process is closely related to organization of a thrombus). 

 Should the newly formed connective tissue not permeate the 

 hematoma, but this chronic aseptic inflammatory process 

 confine itself to the periphery, a connective tissue membrane 

 encapsulating the extravasation is the result. This cyst 

 formation is commonly seen in dogs. 



Describe the process of necrosis. 



Here the suppuration is due to the entrance of pathogenic 

 bacteria into the blood extravasation. Diffused hemorrhagic 

 infiltrations are likely to lead to septic cellulitis ; the hema- 

 toma is changed into an abscess ; septicaemia and pyaemia 

 inay become sequels. 



Describe the symptoms of a contusion. 



There is always more or less sudden swelling except in 

 deep subfacial or intermuscular bruises, where three to four 

 days may pass before the soft fluctuating hematoma shows. 

 Hemorrhagic infiltrations are somewhat hard to the touch* 

 In the first few days there is no cedematous, doughy, hard, 

 painful peripheral swelling ; in fact, this is usually peculiar 

 to an abscess. Later on the contused area becomes harder, 

 fluctuation disappearing as the serum is absorbed and re- 

 placed by cellular elements. Excoriation of the skin over 

 the area of contusion may be seen. Depending on the locality 

 of the contusion, impaired or lost function is apparent : thus, 

 lameness, difficult mastication, apprehension of food, par- 

 alysis, contusion of nerves, spinal cord, insensibility from, 

 contusion of the brain. 



