260 PATHOLOGY OF 



ance to this opinion, as I can agree, to a certain 

 extent, -with the views advocated on either side. 

 The Edinburgh pa&ologiste have, I think, satis- 

 factorily proved that the variations in the ab.-oluir 

 quantity of blood contained within the cerebral 

 vessels as a whole are very limited, and that the 

 brain, consequently, does not present the extreme 

 and rapid sanguineous accumulations which we ob- 

 serve in other organs of the body. And I can, at 

 the same time, equally agree with Dr. Burrows, that 

 the tendency to such an accumulation of blood within 

 the cranium may produce pressure upon the brain 

 and its morbid consequences. The peculiar physical 

 conditions affecting the brain, however, not only 

 confine within narrow limits changes in the quantity 

 of blood present in that organ, but, if I mistake not, 

 they also exercise a still more important influence 

 upon the motion of the blood contained in its capillaries, 

 and through it, upon the cerebral functions. 



I have previously alluded to the physiological law 

 regulating the action of the nervous structures gene- 

 rally, and stated that the incessant motion of the 

 blood through the capillaries of the brain is essential 

 to the performance of its functions. Whenever, 

 therefore, from any cause, external or internal, that 

 capillary circulation is arrested, the functions of the 

 brain immediately cease. If, then, it can be shown 

 that, during an augmented flow of blood to, or its im- 

 peded return from, the brain, the physical conditions 

 under which that organ is placed tend to arrot 

 and obstruct the free passage of the blood through 

 its capillaries, an explanation will, I conceive, be 



