EXCESSIVE EXERCISE OF THE BRAIN. 225 



glass-blowers, smiths, and others, who are obliged 

 to work in an intense light. 



Precisely analogous phenomena occur when, from 

 intense mental excitement, the brain is kept long in 

 a state of excessive activity. The only difference 

 is, that we can always see what happens in the eye, 

 but rarely what takes place in the brain. Occasion- 

 ally, however, cases of fracture of the scull occur, 

 in which, from part of the bone being removed, we 

 can see the quickened circulation in the vessels of 

 the brain as easily as in those of the eye. Sir Ast- 

 ley Cooper had a young gentleman brought to him 

 who had lost a portion of his scull just above the 

 eyebrow. " On examining the head," says Sir Ast- 

 ley, " I distinctly saw the pulsation of the brain was 

 regular and slow ; but at this time he was agitated 

 by some opposition to his wishes, and directly the 

 blood was sent with increased force to the brain, the pul- 

 sation became frequent and violent; if, therefore," con- 

 tinues Sir Astley, "you omit to keep the mind free 

 from agitation, your other means will be unavailing" in 

 the treatment of injuries of the brain.* We are con- 

 scious, indeed, of a flow of blood to the head when 

 we think intently, or are roused by passion ; and the 

 distension of the small vessels of the brain is not the 

 less real or influential on account of its being hidden 

 from our view. Too often it reveals itself by its 

 effects when least expected, and leaves traces after 

 death which are but too legible. How many public 

 men, like Whitbread, Romilly, Castlereagh, and 

 Canning, urged on by ambition or natural eagerness 

 of mind, have been suddenly arrested in their career 

 by the inordinate action of the brain induced by in- 

 cessant toil! And how many more have had their 

 mental power for ever impaired by similar excess! 

 When tasked beyond its strength, the eye becomes 



* See Sir A. Cooper's Lecture on Surgery, by Tyrrel, vol i, 

 p. 279. 



