TREATMENT OF INFLAMMATION. 189 



kind will, of course, occasionally co-operate in their 

 action. 



The causes accelerating the flow of blood into the 

 aorta are, with the exception of bodily exercise and 

 certain medicinal stimulants, chiefly of an emotional 

 nature. That the force and frequency of the ven- 

 tricular contractions are at once increased by anger 

 and other passions, is a fact familiar to every one. 

 And it must also be evident to every careful ob- 

 server, that the lateral pressure of the aortic blood is 

 at the same time augmented, and that this occurs in 

 a ratio more or less intimately connected with the 

 abruptness of the application, as well as with the 

 intensity or power of the exciting cause of the 

 quickened circulation. In no other manner can we 

 explain the bursting of blood-vessels, so long noticed 

 as an occasionally fatal effect of a fit of anger, or 

 the equally striking instances recorded by surgical 

 writers, in which ligatures upon large arteries have 

 been displaced, and fatal hsemorrhage thus induced, 

 in consequence of the patients being either affected 

 by powerful mental emotion, yielding to the pas- 

 sions, or making some violent muscular effort. And, 

 to take cases of more frequent occurrence, who has 

 not during exercise personally experienced the very 

 different sensations caused by a gradual and a sudden 

 increase in the action of the heart ? In the one case 

 the arteries and capillaries seem readily to accom- 

 modate their calibre to the gradually increased 

 quantity of blood poured into the aorta, and the only 

 sensation induced by the accelerated circulation is a 

 not unpleasant glow in the thorax, rapidly diffusing 



