424 PRACTICE OF PHYSIC. 



vegetable poisons show chiefly a narcotic, or strongly sedative 

 power, it is probably by this power that they produce epilepsy, 

 and therefore belong to this head of the causes acting by col- 

 lapse. " I allege that this consequence frequently arises when 

 no inflammatory state of the stomach appears : and so far as I 

 can perceive, the substances are frequently known to Vje narco- 

 tics, and to act by producing a collapse." 



MCCCVI. Under the head of the remote causes producing 

 epilepsy, we must now mention that peculiar one whose opera- 

 tion is accompanied with what is called the Aura Epileptica. 

 This is a sensation of something moving in some part of the 

 limbs or trunk of the body, and from thence creeping upwards 

 to the head ; and, when it arrives there, the person is immediate- 

 ly deprived of sense, and -falls into an epileptic fit. This mo- 

 tion is described by the persons feeling it, sometimes as a cold 

 vapour, sometimes as a fluid gliding, and sometimes as the sense 

 of a small insect creeping along their body ; and very often they 

 can give no distinct idea of their sensation, otherwise than as in 

 general of something moving along. This sensation might be 

 supposed to arise from some affection of the extremity or other 

 part of a nerve acted upon by some irritating matter ; and that 

 the sensation, therefore, followed the course of such a nerve : 

 but I have never found it following distinctly the course of any 

 nerve ; and it generally seems to pass along the teguments. It 

 has been found in some instances to arise from something press- 

 ing upon or irritating a particular nerve, and that sometimes in 

 consequence of contusion or wound : but instances of these are 

 more rare; and the more common consequence of contusions 

 and wounds is a tetanus. This latter effect wounds produce, 

 without giving any sensation of an aura or other kind of mo- 

 tion proceeding from the wounded part to the head ; while, on 

 the other hand, the aura producing epilepsy often arises from a 

 part which had never before been affected with wound or con- 

 tusion, and in which part the nature of the irritation can sel- 

 dom be discovered. 



It is natural to imagine, that this aura epileptica is an evi- 

 dence of some irritation or direct stimulus acting on the part, 

 and from thence communicated to the brain, and should there- 

 fore have been mentioned among the causes acting by excite- 



