366 DISEASES CEASS IV. I. 1. 



affected by their sympathy with those of the skin, as appears from 

 the defect of secretion in ulcers during the cold fits of agues. 



The motions of this extensive system of capillaries, thus asso- 

 ciated by direct sympathy, are also associated with those of the 

 heart and arteries, sometimes by reverse and sometimes by di- 

 rect sympathy; and thus constitute simple fever. The cold pa- 

 roxysm of which consists in their torpor, and the hot one in their 

 orgasm, or increased activity. 



I. Of the Action of Vomiting. 



The manner in which the stomach and the diaphragm and 

 abdominal muscles acquire their associate action in vomiting, 

 requires some attention. It is not probable that this action of 

 vomiting occurs before nativity; as the uniform application of 

 the nutritive liquor amnii to the mouth of the foetus, and the 

 uniform expenditure of its nourishment, would not seem to give 

 occasion to too great temporary repletion of the stomach; and 

 would preclude the deglutition of any improper material. After 

 nativity the stomach of the child may be occasionally too much 

 distended with milk; as previous hunger may induce it to over* 

 gorge itself; and by repeated efforts the act of vomiting is learned, 

 as a means of getting free from a disagreeable sensation. Thus 

 when any disgustful material, as a bitter drug, is taken into the 

 mouth; certain retrograde motions of the tongue and lips are pro- 

 duced, for the purpose of putting the disagreeable material out of 

 the mouth again. 



When the stomach is disagreeably stimulated by the distention 

 of acrimony of the aliment, a similar effort to regurgitate it must 

 occur; and by repeated trials the action of the diaphragm and 

 abdominal muscles by squeezing the stomach assists its retro- 

 grade exertion to disgorge its contents. In the same manner 

 when a piece of gravel is pushed into the urethra, or a piece of 

 indurated bile into the neck of the gall-bladder, after they have 

 been in vain pressed forward by the usual motions of those 

 ducts, they return into the bladders of gall and urine by the re- 

 trograde motions of them. 



That this is one mode in which vomiting is induced, appears 

 from the instantaneous rejection from the stomach occasioned 

 by some nauseous drug, or from some nauseous idea; and lastly, 

 from the voluntary power, which some people have been said to 

 have acquired, of emptying their stomachs, much in the same 

 manner as ruminating animals bring up the grass from their first 

 stomach. 



There are nevertheless many modes by which these inverted 



