CIRCULAR UISTURItANCES. 137 



Arterial hyperemia of short duration is less serious than 

 it would be if long continued, thus, active pulmonary hyper- 

 aemia is occasionally aborted in the horse and such animals are 

 usually ready fur service in 24 to 48 hours, but if active i)ul- 

 nionar)' hyperemia continues for 24 hours it is succeeded by 

 inflammation (pneumonia). 



Arterial hyperemia varies in different organs. Affections 

 of the more highly organized structures are usually more seri- 

 ous. 



Physioloc/ic arterial liypcreiiiia is a condition in whiclt 

 there is an increased amount of blood flowing into a tissue be- 

 cause of increased physiologic demand, thus during gastric di- 

 gestion an excess of blood passes to the stomach through the 

 gastric arteries. 



Thcrapcutii arterial hxl^eremia. when properlv produced 

 in a diseased part, results in (a), diminished j^ain, (b), resorp- 

 tion of inflammatorv exudate, hemorrhagic extravasate, and 

 (^edematous transudate, (c) increased nutrition, thus bv the al- 

 ternate use of Cold and hot applications an arterial h\'peremia 

 is produced and is of value in strained tendons, bruises, etc. 



Pathologic arterial hyperemia, may produce hypertrojihy. 

 hyperplasia and permanent arterial dilatation. l^xcessi\'e de- 

 velopment of a part (hyjaertrophy or h}-peri)lasia) may result 

 froui a long continued acti\'e hyperemia as in thickening of the 

 skin as a result of continued application of blistering agents, 

 Init arterial hvperemia is as a rule of short duration for it 

 r.s\iall\- terminates in recovery or is succeeded by inflannnation. 



