2,c5 OF VERTIGO. SECT. XX. 9. 10. 



taifed or turned in his bed, prefently induce the 

 vomiting by fuperadding a degree of vertigo. 



9, And converfely it is very ufual with thofe, 

 whofe ftomachs are affected from internal caufes, 

 to be afflidted with vertigo, and noife in the head ; 

 fuch is the vertigo of drunken people, which con- 

 tinues, when their eyes are clofed, and themfelves 

 in a recumbent pofture, as well as when they are in 

 an .erect pofture, and have their eyes open. And 

 thus the irritation of a (ione in the bile-duel, or in 

 the ureter, or an inflammation of any of the 

 inteftines, are accompanied with vomitings and 



vertigo. 



In thefe cafes the irritative motions of the fto- 

 mach, which are in general not attended to, become 

 fa changed by fome unnatural flimulus, as to be* 

 come uneafy, and excite our ienfation or attention. 

 And thus the other irritative trains of motions, 

 which are aflbciated with it, become difordered by 

 their fympathy. The fame happens, when a piece 

 of gravel (licks in the ureter, or when fome part of 

 the inteftinal canal becomes inflamed. In thefe 

 cafes the irritative mufcular motions are firft dif- 

 turbed by unufuai ftimulus, sad a difordered aclion 

 of the fenfual motions, or dizzinefs enures. While 

 in fea-ficknefs the irritative fepfual motions, as. 

 vertigo, precedes ; and the difordered ? irritative 

 mufcular motions, as thofe of the-iloia^ch in yp- 

 mhing, follow. 



10. When thefe irritative motions are difturbed ? 

 if the degree be not very great, the exertion of 

 voluntary attention to any other object, or any 

 fadden fenfation, will disjoin thefe new habits of 

 motion. Thus fome drunken people have becpme 

 fober immediately, when any accident has ftrongly 

 excited their attention ; and fea iicknefs has vanifn- 

 ed, when the fhip has been in danger. Hence 

 wheu our attention to other objecls is moft relaxed, 

 b? as. 



