LECTURE XVI 

 PATHOLOGY— Co^^inwed 



Hemorrhag"e. — Any escape of blood from its natural channels, 

 whetlicr into the tissues, or cavities, or upon the body surface, 

 is termed "hemorrhage." 



Cannes. — Hemorrhage is caused by injury to the vessel walls, 

 as when cut or torn ; diseases of the vessel walls, such as fatty 

 or calcareous degeneration ; bacterial toxins, injuring the capil- 

 laries; excessive blood pressure inside the vessel, as in hyper- 

 trophy of the heart with excessive strength and activity, result- 

 ing in rupture of the vessels ; change i" the quality of the blood, 

 with weakness in the vessel walls, as in purpura, a common 

 disease of horses. 



Dropsy. — Any abnormal collection of serous fluid in any cav- 

 ity or tissue of the body is designated as "dropsy." This may 

 occur in the abdominal cavity, in the chest cavity, ventricles or 

 the brain, or the loose tissues under the skin. Of those places 

 outside the large cavities, the most common are the limbs and 

 lower portions of the abdomen, as the swelling under the belly 

 of a mare heavy with foal and lacking exercise, or a swelling 

 of sheath and belly in a case of recent castration with infection 

 and lack of exercise. Dropsical fluid is usually of a pale straw 

 color, nearly neutral in chemical reaction, and slightly heavier 

 than water. 



Cause of dropsy. — Any local increase of blood pressure ; any 

 interference with flow of blood in the veins; or obstruction in 

 capillaries, which is quite common in diseases of the liver or 

 kidneys will cause dropsy. Note the similarity of these causes 

 to the causes of passive hyperemia. Dropsy may be either 

 general or local. 



General dropsy may be due to conditions associated with 

 anemia, passive hyperemia, heart trouble, or kidney disease, 

 and may affect the subcutaneous connective tissue over a large 

 area, and any of the serous body cavities. 



Local dropsy is limited to some one organ or cavity, and it 



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