SPASMODIC AFFECTIONS. 419 



serves, by the influence of imagination, to renew it. I know a 

 person who upon the mention of ipecacuanha was seized with 

 sickness and nausea : and a thousand such instances are mention- 

 ed in the records of physic ; so that patients of delicate im- 

 agination are to be treated with suitable delicacy." 



MCCXCIV. I come now to the fourth head of the irritations 

 applied immediately to the brain, and which I apprehend to be 

 that of the over-distention of the blood-vessels in that organ. 

 That such a cause operates in producing epilepsy, is probable 

 from this, that the dissection of persons dead of epilepsy has com- 

 monly discovered the marks of a previous congestion in the blood- 

 vessels of the brain. This, perhaps, may be supposed the ef- 

 fect of the fit which proved fatal : but that the congestion was 

 previous thereto, is probable from the epilepsy being so often 

 joined with headach, mania, palsy, and apoplexy ; all of them 

 diseases depending upon a congestion in the vessels of the brain. 

 The general opinion receives also confirmation from this cir- 

 cumstance, that, in the brain of persons dead of epilepsy, there 

 have been often found tumours and effusions, which, though 

 seemingly not sufficient to produce those diseases which depend 

 on the compression of a considerable portion of the brain, may, 

 however, have been sufficient to compress so many vessels as to 

 render the others, upon any occasion of a more than usual tur- 

 gescence, or impulse of the blood into the vessels of the brain, 

 liable to an over-distention. 



MCCXCV. These considerations alone might afford foun- 

 dation for a probable conjecture with respect to the effects of 

 over-distention. But the opinion does not rest upon conjec- 

 ture alone. That it is also founded on fact, appears from 

 hence, that a plethoric state is favourable to epilepsy ; and 

 that every occasional turgescence, or unusual impulse of the 

 blood into the vessels of the brain, such as a fit of anger, the 

 heat of the sun, or of a warm chamber, violent exercise, a sur- 

 feit, or a fit of intoxication, are frequently the immediate exciting 

 causes of epileptic fits. 



MCCXCVI. I venture to remark further, that a piece of 

 theory may be admitted as a confirmation of this doctrine. As 

 I have formerly maintained, that a certain fullness and tension 

 of the vessels of the brain is necessary to the support of its or- 



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