Class IV. 2. 1. 12. OF ASSOCIATION. 407 



tive aflbciation, but not by fenfitive afTociation. The event was, 

 that as foon as the gums became fore with a flight ptyalifm, the 

 pains about the head and vertigo gradually diminifhed,and during 

 the forenefs of his gums entirely ceafed ; but I believe recurred 

 afterwards, though in lefs degree. 



The idea of inflaming the membranes of the teeth to pro- 

 duce increafed fenfation in them, and thus to prevent their 

 irritative connexion with thole of the cranium, was taken from 

 the treatment of trifmus, or locked jaw, by endeavouring to in- 

 flame the injured tendon ; which is faid to prevent or to remove 

 the fpafm of the mufcles of the jaw. See Ciafs III. 1. 1. 13. 

 and 15. 



M. M. Emetics. Blifters. IfTues about the head. Extrac- 

 tion of decayed teeth. Slight falivation. Sorbentia. Incitantia. 

 Galvanifm. 



A lady was fuddenly feized with violent vertigo, fo as to pre- 

 vent her from walking fafely acrofs the room, this was attended 

 with confiderable diminution of fight ; and after various evacua- 

 tions, and other medicines, had been tried without cure, Mr. 

 Volta's galvanic pillar was ufed, confiding of about 30 plates of 

 filver, the diameter of about one inch and half, and as many 

 zinc plates, with interpofed circles of cloth moiftened with brine. 

 A wire connected with each end of this pillar was approached 

 repeatedly to her temples, which were previoufly moiftened with 

 brine, and 100 galvanic fhocks were daily pafled through the 

 optic nerves, which foon appeared to be of great advantage, and 

 ihe foon recovered, both from the vertigo and dimnefs of %ht. 

 12. Vertigo ebriofa. Vertigo from intoxication is owing to 

 the aflbciation of the irritative ideas of vifion with the irritative 

 motions of the ftomach. Whence when thefe latter become 

 much increafed by the immoderate ftimulus of wine, the irrita- 

 tive motions of the retina are produced with lefs energy by re- 

 verfe fympathy, and become at the fame time fucceeded by fen- 

 fation in confequence of their decreafed action. See Sect. XXI. 

 3. and XXXV. 1.2. So converfely when the irritative mo- 

 tions of vifion are increafed by turning round, or by our unac- 

 cuitomed agitation at fea, thofe of the ftomach become inverted 

 by reverfe fympathy, and are attended in confequence with difa- 

 greeable fenfation. "Which ojecreafed action of the ftomach is 

 in confequence of the increafed expenditure of the fenfbrial 

 power on the irritative ideas of viiion, as explained in Vertigo 

 rotatoria. 



Whence though a certain quantity of vinous fpirit llimulates 

 the whole fyitem into increafed action, and perhaps even in- 

 creafes the fecretionof fenfcrial nower in the brain ; vet as foon 



3 



