CIASS III. I. I. 8. OF VOLITION. 287 



verie or somnambulation. About half an hour before the ex* 

 pectecl return of the fit three or four grains of opium were exhi- 

 bited, and then tincture of opium was given in warm brandy and 

 water about twenty or thirty drops every half hour, till the eyes 

 became somewhat inflamed, and the nose began to itch, and by 

 the sharp movements of the patient, or quick speech, an evident 

 intoxication appeared; and then it generally happened that the 

 pain ceased. But the effects of this large dose of opium was 

 succeeded by perpetual sickness and efforts to vomit, with great 

 general debility all the succeeding day. 



The rationale of this temporary cure from the exhibition of 

 opium and vinous spirit depends on the great expenditure of 

 sensorial power in the increased actions of all the irritative mo- 

 tions, by the stimulus of such large quantities ef opium and vinous 

 spirit; together with the production of much sensation, and 

 many movements of the organs of sense or ideas in consequence 

 of that sensation; and lastly, even the motions of the arterial 

 system become accelerated by this degree of intoxication, 

 all which soon exhausted so much sensorial power as to re- 

 lieve the pain; which would otherwise have caused convulsions 

 or insanity, which are other means of expending sensorial power. 

 The general debility on the succeeding day, and the particular 

 debility of the stomach, attended in consequence with sickness 

 and frequent efforts to vomit, were occasioned by the system 

 having previously been so strongly stimulated, and those parts 

 in particular on which the opium and wine more immedi- 

 ately acted. This sickness continued so many hours as to 

 break the catenation of motions, which had daily reproduced 

 the paroxysm; and thus it generally happened, that the whole 

 disease ceased for some weeks or months from one great intoxi- 

 cation, a circumstance not easily to be explained on any other 

 theory. 



The excess or defect of motion in any part of the system oc- 

 casions the production of pain in that part, as in Sect. XII. 1. 6. 

 This defect or excess of fibrous action is generally induced by 

 excess or defect of the stimulus of objects external to the moving 

 organ. But there is another source of excessive fibrous action, 

 and consequent pain, which is from excess of volition, which 

 is liable to affect those muscles, that have weak antagonists; 

 as those which support, the under jaw, and close the mou'h 

 in biting, and those of the calf of the leg; which are thus liable 

 to fixed or painful contractions, as in trismus, or locked jaw, and 

 in the cramp of the calf of the leg; and perhaps in some colics, 

 as in that of Japan: these pains, from contraction arising from 

 excess of volition in the part from the want of the counteraction 



