LECTURE XV. 



PATHOLOGY. 



Haemorrhage is any appearance of blood outside of the 

 natural channels. 



Causes. — (i) Injury to the vessel walls, as when cut or 

 torn; (2) diseases of the vessel walls, e. g., fatty or calcareous 

 degeneration; (3) excessive blood pressure inside the vessel, as 

 in hypertrophy of the heart with excessive strength and activity 

 resulting in rupture of the vessels; (4) change in the quality 

 of the blood with weakness in the vessel walls. 



Dropsy is any abnormal collection of serous fluid in any cav- 

 ity or tissue of the body. This may occur in the abdominal 

 cavity, in the chest cavity, ventricles of the brain, or in loose 

 tissues under the skin. Of those places outside the large cavi- 

 ties, the most common are the limbs and lower portions of ab- 

 domen. Dropsical fluid is usually of pale straw color, nearly 

 neutral in chemical reaction and slightly heavier than water. 



Cause of dropsy. — (1 ) Any local increase of blood pressure, 

 (2) any interference with flow of blood in the veins, (3) obstruc- 

 tion in capillaries, which is quite common in diseases of the liver. 



Dropsv may be either general or local. 



General dropsy may affect the sub-cutaneous connective tis- 

 sue over a large area, and any of the serous body cavities. It 

 may be due to conditions associated with anaemia, heart trouble, 

 or kidney disease. 



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

 may be due to local mechanical obstruction in the veins or may 

 occur as a result of inflammation, as in pleurisy where there is 

 an inflammation of the pleura and dropsy into the pleural sacs. 



Hypertrophy is any enlargement of any part or organ of 

 the body. It may be due to either an increase in the number 

 of elements, or an increase in the size of existing elements, or 

 to a combination of two conditions. Hypertrophy may be either 

 physiological, healthy, or pathological, diseased. 



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