EPILEPSY AND APOPLEXY. 265 



irregularities in the motion of the blood as a source 

 of disordered action of the brain, I cannot do better 

 than quote the same writer's estimate of the impor- 

 tance of this study. " The circulation within the 

 cranium " says Dr. John Reid, " possesses several 

 peculiarities, which not only excite the attention of 

 the anatomist, but are constantly referred to by the 

 physiologist and pathologist, in their discussions 

 upon the functions and diseases of the important 

 organ there contained, viz. the encephalon. The 

 derangements of the circulation within the cranium, 

 are so often followed by such serious consequences, 

 that it becomes an object of the highest practical 

 importance to endeavour to ascertain the nature 

 and cause of those derangements." 



It will be seen that, according to this doctrine, the 

 sudden compression of the brain (whether produced 

 by an external injury, as by fracture and depression of 

 the cranium, or by an internal disorder of the circu- 

 lation) in giving rise to coma, acts by the stoppage 

 of the blood's motion in the capillaries of the nervous 

 structures. For the same pathological effect will 

 always follow the same cause, so long as the sur- 

 rounding conditions are unchanged. 



Thus, the tendency to the accumulation of blood 

 in the vessels of the brain, may arise from a suddenly 

 increased influx of arterial blood, as from great ex- 

 citement or exertion, or from a hypertrophied heart ; 

 or it may be induced by any circumstance impeding 

 the return of blood from the lateral sinuses. And 

 both in epilepsy and apoplexy, we observe in the 

 predisposing and exciting causes a frequent proneness 



