TKEATMENT OF INFLAMMATION. 195 



condition is, in each case, distinctly referrible to the 

 resistance or backward pressure of the aortic blood 

 as its universal and proximate cause. And in the 

 treatment of every form of heart disease, the pre- 

 vention of a morbid accumulation of blood in the 

 aorta, and the diminution of the pressure of the fluid 

 mass to a point as low as is consistent with the 

 proper performance of its physiological uses, con- 

 stitute hygienic and therapeutic principles of the 

 greatest importance. 



We have now to consider the third effect of an 

 unnatural increase in the pressure of the aortic blood ; 

 viz. an unusual accumulation of fluid in, and conse- 

 quent distension of, the rest of the arterial system. 

 While walking, or taking any other kind of moderate 

 exercise, we can, by our sensations and by the greater 

 pulsation of the superficial arteries, trace the gradual 

 passage of the accumulated blood from the aorta into 

 the smaller arterial branches. In these cases the 

 accumulation consequent on the increased dispro- 

 portion between the influx and efflux of arterial 

 blood merely occasions a slight increase in the 

 calibre of the smaller vessels, and a more rapid cir- 

 culation through the capillaries and veins, with 

 increased activity of the various functions served by 

 the columns of blood traversing the former vessels. 



o 



But when, as during violent exercise, the pressure of 

 the arterial blood is more considerable, it not only in- 

 duces inordinate pulsation of the different arteries, but 

 also occasionally causes extravasation of blood from 

 the rupture of some of the smaller and weaker vessels ; 



o 2 



