60 PATHOLOGY. 



their walls, thus obstructing the blood current; (4) both kinds 

 of corpuscles and the blood plasma may pass through walls of 

 small veins and capillaries. Inflamed tissue may lose vitality, 

 degenerate and die. 



Inflammation varies according to (a) resisting power of 

 tissue, (b) activity of cause, (c) length of time cause is in ac- 

 tion. 



Causes of inflammation. — Are: (1) Mechanical injury, 

 chemical action, excessive functional activity, extremes of heat 

 and cold, etc. Inflammation thus caused has little tendency to 

 spread beyond the part injured, and there is usually little or 

 no pus unless pus germs invade the inflamed area. 



(2) Microbes, micro-organisms and germs are synonymous 

 terms as commonly used. These can cause inflammation without 

 the aid of local injury. Inflammation may be caused directly 

 by their mechanical presence and activity, or it may appear as 

 the result of irritation caused by chemical agents which the 

 germs manufacture. Microbic inflammation may be either sep- 

 tic or infective. 



Terminations. — Inflammation may terminate in (a) resolu- 

 tion, (b) death of the tissue, or (c) new growths. 



Resolution. — Tn this case the exudate is removed by the 

 lvmphatics and veins ; blood current starts again in the smali 

 vessels ; the corpuscles move away in the re-established current 

 or else become degenerated like the fibrin of the exudate and 

 then removed, and the organ or tissue becomes normal again. 



Local death. — If death of the part occurs, the inflammation 

 goes on until part or all of the inflamed organ or tissue dies. 



If new growths occur, there develop new tissues, e. g., tu- 

 mors, granulations in wound, and scar tissue. 



FEVER. 



Definition. — Fever is a pathological condition characterized 

 by an excess of heat in the body. Xot a disease, merely a symp- 

 tom of disease. 



Cause. — Any disturbance that causes an increase of heat 

 production or decrease of heat loss, usually the former. Normal 

 temperature of horse is 100 degrees F. to 101.5 degrees F. One 

 hundred and four degrees F. is called high, 106 degrees F. very 



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