SPASMODIC AFFECTIONS. 423 



MCCCIII. A third cause acting by collapse, and producing 

 epilepsy, is horror ; or a strong aversion suddenly raised by a 

 very disagreeable sensation, and frequently arising from a sym- 

 pathy with the pain or danger of another person. As horror is 

 often a cause of syncope, there can be no doubt of its manner 

 of operating in producing epilepsy ; and it may perhaps be ex- 

 plained upon this general principle, That, as desire excites ac- 

 tion and gives activity, so aversion restrains from action, that is, 

 weakens the energy of the brain ; and, therefore, that the higher 

 degrees of aversion may have the effects of producing syncope 

 or epilepsy. 



MCCCIV. A fourth set of the causes of epilepsy, which I 

 suppose also to act by collapse, are certain odours, which occa- 

 sion either syncope or epilepsy ; and, with respect to the former, 

 I have given my reasons (MCLXXXII.) for supposing odours 

 in that case to act rather as disagreeable than as sedative. 

 These reasons will, I think, also apply here ; and perhaps the 

 whole affair of odours might be considered as instances of the 

 effect of horror, and therefore belonging to the last head. 



" With respect to those odours, it might be suspected, that 

 they act by a directly sedative power, but that cannot be ad- 

 mitted, because their operation on the most part of men is di- 

 rectly stimulant ; but it must be referred to a strongly disagree- 

 able sensation, which, when producing no reaction, causes syn- 

 cope, but with reaction in particular persons, causes hysteria and 

 epilepsy. 



"Here it is to be observed, that although in general it is odours 

 which give the most disagreeable sensations, yet it is probable, 

 that the stomach also possesses a sensibility liable to be affected 

 with impressions merely as disagreeable; and thence the aversion 

 towards particular foods in certain persons producing nausea, 

 vomiting, syncope, and epilepsy." 



MCCCV. A fifth head of the causes producing epilepsy by 

 collapse, is the operation of many substances considered, and for 

 the most part properly considered, as poisons. Many of these, 

 before they prove mortal, occasion epilepsy. This effect, in- 

 deed, may in some cases be referred to the inflammatory opera- 

 tion which they sometimes discover in the stomach and other 

 parts of the alimentary canal ; but, as the greater part of the 



