3J2 PRACTICE OF PHYSIC. 



many of them act by nausea, or by the disagreeable sensation 

 which they give. Many of them may be suspected to act by seda- 

 tive power, and therefore by debility; this is illustrated by opium, 

 which always in a large and often in a small dose excites vomit- 

 ing, and by tobacco. That a disagreeable sensation often operates, 

 appears from the vomiting attending gastritis, excited by the 

 mildest matters thrown into the stomach. Nay, as under debi- 

 lity, action is always uneasy, so it goes so far in the stomach as 

 to occasion vomiting from every thing thrown into it, when the 

 substance is nowise stimulant, nor is there any suspicion of topi- 

 cal affection to render action uneasy. 



" When an obstruction of the pylorus occasions vomiting, I 

 think it must be referred to the uneasy sensation arising from 

 the accumulation of matters in the stomach ; at least that it 

 operates so in the case of warm water, is probable ; for this cer- 

 tainly cannot operate by its stimulus. It may indeed act by a 

 disagreeable sensation, which is increased by oil added to it, but 

 it operates especially by its bulk producing a constriction of the 

 pylorus, and thereby uneasiness. 



" It cannot be imputed to disagreeable sensation, when some 

 of the mildest substances, as an egg, in particular persons ex- 

 cite vomiting. 



" The doctrine of debility occasioning vomiting is confirmed 

 by all we said formerly on the vomiting which occurs at the be- 

 ginning of fevers (XLI V.). 



" But enough on the subject of vomiting, as shewing the proxi- 

 mate cause of dyspepsia." 



MCXCIV. The imbecility of the stomach, and the conse- 

 quent symptoms (MCXC.), may, however, frequently depend 

 upon some organic affection of the stomach itself, as tumour r 

 ulcer, or scirrhosity ; or upon some affection of other parts of 

 the body communicated to the stomach, as in gout, amenorr- 

 hoea, and some others. In all these cases, however, the dys- 

 peptic symptoms are to be considered as secondary or sympa- 

 thic affections, to be cured only by curing the primary disease. 

 Such secondary and sympathic cases cannot, indeed, be treated 

 of here ; but, as I presume that the imbecility of the stomach 

 may often take place without either any organic affection of this 

 part, or any more primary affection in any other part of the body ; 



