SECT. XXXVI. a. PERIODS OF DISEASES. 517 



catenated \vith certain portions of time, or degrees 

 of exhauftion, or other diurnal habits of life. And 

 if the pain of hunger be not relieved by taking 

 food at the ufual time, it is liable to ceafe till the 

 next period of time or other habits recur , this is 

 not only true in refpec~l to our general deiire of 

 food, but the kinds of it alfo are governed by this 

 periodical habit ; infomuch that beer taken to break- 

 fail will diilurb the digeftion of thofe, who have 

 been accuftomed to tea ; and tea taken at dinner 

 will difagree with thofe, who have been accuftomed 

 to beer. Whence it happens, that thofe, who have 

 weak ftomachs, will be able to digeft more food, if 

 they take their meals at regular hours; becaufe they 

 have both the ftimulus of the aliment they take, and 

 the periodical habit, to aflat their digeftion. 



The periods of emptying the bladder are not only 

 dependent on the acrimony or diflention of the 

 water in it, but are frequently catenated with ex- 

 ternal cold applied to the ikin, as in cold bathing, 

 or wafhing the hands ; or with other habits of life, 

 as many are accuftomed to empty the bladder be- 

 fore going to bed, or into the houfe after a journey, 

 and this whether it be full or not. 



Our times of refpiration are not only governed 

 by the ftimulus of the blood in the lungs, or our 

 defire of frefh air, but alfo by our attention to the 

 hourly objecls before us. Hence when a perfon is 

 earneiily contemplating an idea of grief, he forgets 

 to breathe, till the fenfation in his lungs becomes 

 very urgent ; and then a figh fuccecds for the pur- 

 pofe of more forcibly pufhing forwards the blood, 

 which is accumulated in the lungs. 



Our times of refpiration are alfo frequently go- 

 verned in part by our want of a fteady fupport for 

 the a6lions of our arms, and hands, as in threading 

 a needle, or hewing wood, or in fwimming; when 

 we are intent upon thefe objefts, we breathe at 



the 



