of the Heart and Arteries. 31 
inflammation. In a case of hemorrhage from one of the sinuses 
of the brain, a very judicious physician lately prescribed the 
digitalis : if the effect of this medicine tends principally to 
diminish the action of the heart, as is commonly supposed, it 
was more likely to be injurious than beneficial, since a venous 
plethora must be increased by the inactivity of the heart ; but 
if the digitalis diminishes the general tension of the arteries, 
in a greater proportion than it affects the motion of the heart, 
it may possibly be advantageous in venous hemorrhages. We 
have, however, no sufficient authority for believing, that it has 
any such effect on the arterial system in general. 
Although the arguments, which I have advanced, appear to 
me sufficient to prove, that, in the ordinary state of the circu- 
lation, the muscular powers of the arteries have very little 
effect in propelling the blood, yet I neither expect nor desire 
that the prevailing opinion should at once be universally aban- 
doned. I wish, however, to protest once more against a hasty 
rejection of my theory, from a superficial consideration of 
cases, like that which has been related by Dr. Clarke ; and 
to observe again, that the objections, which I have adduced, 
against the operation of the muscular powers of the arteries 
in the ordinary circulation, not being applicable to these cases, 
they are by no means weakened by any inferences which can 
be drawn from them. v 
ERRATA. 
In the last volume of the Philosophical Transactions, page 183, line Z5, for read 
j : page 184, at the end, add, is denoted by av : page 186, line 4, for when ced, 
read whence d. 
