

SECT. XXXV. a. DISEASES OF ASSOCIATION. 507 



that though vomiting is in general produced by the 

 defect of this ftimulus of pleafurable fenfation, as 

 When a naufeous drug is adminiftered ; yet in long 

 continued vomiting, as in fea-ficknefs, or from habi- 

 tual dram-drinking, it arifes from deficiency of fen- 

 foii.il power, "which in the former cafe is exhaufted 

 by the increafed exertion of the irritative ideas of 

 vifion, and in the latter by the frequent application 

 of an unnatural ftimulus. 



4. An example of the fourth circumftance above 

 mentioned, where both the primary arid fecondary 

 parts of a train of motions proceed with energy lefs 

 than natural, may be obferved in the dyfpncea, which 

 occurs in going into a very cold bath, and which 

 has been defcribed and explained in Seel. XXXII. 3. 2* 



And by the increafed debility of the pulfations of 

 the heart and arteries during the operation of an 

 emetic. Secondly, from the flownefs and intermif- 

 fion of the pulfations of the heart from the inceffant 

 efforts to vomit occafioned by an overdofe of digi- 

 talis. And thirdly, from the total floppage of the 

 motions of the heart, or death, in confequence of 

 the torpor of the ftomaeh, when affected with the 

 commencement or cold paroxyfm of the gout. See 

 Sea. XXV. 17. 



II. i. The primary and fecondary parts of the 

 trains of fenfitive affociadon reciprocally affect each 

 other in different manners, i. The increafed fen- 

 fation of the primary part may eeafe, when that of 

 the fecondary part commences. 2. The increafed 

 action of the primary part may ceafe, when that of 

 the feeondary part commences. 3. The primary 

 part may have increafed fenfation, and the fecon- 

 dary part increafed action. 4. The primary part 

 may have increafed action, and the fecondary part 

 increafed fenfation. 



Examples of the firft mode, where the increafed 

 fenfation of the primary part of a.irain of fenfitive 

 afTociation ceafes, when that of the fecondary part 

 I. LI commences? 



