234 EXCESSIVE EXERCISE OF THE BRAIN. 



discovery which he hoped would lead him to for- 

 tune and distinction. To effect it the sooner, he 

 resolved to shut himself up in his laboratory for 

 several successive days ; and, the better to banish 

 sleep and to raise himself to the level of his la- 

 bours, he prepared a variety of stimulants. A sing-- 

 ing girl shared his retreat ; he drank spirits, smelled 

 frequently odoriferous substances, and sprinkled the 

 room with eau de Cologne. The combined action 

 of all these means, added to the heat of his furnace, 

 caused such a degree of cerebral excitement that, 

 at the end of eight days, the most furious delirium 

 took place, followed by a regular attack of mania 

 If any thing can demonstrate the mutual influence 

 of mind and brain, it is surely a case like this, a 

 case which it is impossible to read without perceiv- 

 ing how easily the cerebral affection might have 

 been of the violent inflammatory character, which 

 terminates, in a few days, in life or in death; or 

 of the febrile character, that lasts for one or two 

 months, and leaves the mind for ever reduced in 

 tone and vigour. 



It is well remarked by Tissot, that the disorders 

 produced by the efforts of the mind fall soonest 

 upon such as are incessantly engaged in the contem 

 plation of the same object. In this case, he adds, 

 there is only one part of the sensorium (brain) acted 

 upon, and that is kept always on the stretch ; it is not 

 relieved by the action of the other parts, and therefore 

 is sooner fatigued and injured ; the same rule holding 

 with the brain as with the muscles, that the exer- 

 cise which, if divided among the different parts of 

 which it is composed, will strengthen them, will, ii 

 confined to a few, exhaust and impair them. Boer- 

 haave himself, after a long period of intense think- 

 ing, suffered for six weeks from excitement of the 

 brain, bordering on madness, and characterized by 

 that want of sleep, irritability, and indifference to 



