265 RETROGRADE SECT. XXIX. n. tv 



eould not make them regurgitate their contained fluid into the 

 bowels. 



I am not indeed certain, that the nerve was not at the fame 

 time included in the ligature, and thus the lymphatic rendered 

 unirritable or lifelefs ; but this however is certain, that it is riot 

 any quantity of any ftimulus, which induces the veflels of animal 

 bodies to revert their motions ; but a certain quantity of a cer- 

 tain ftimulus, as appears from wounds in the ftomach, which do 

 not produce vomiting ; and wounds of the inteftines, which do 

 not produce the cholera morbus. 



At Nottingham, a few years ago, two flioemakers quarrelled, 

 and one of them with a knife, which they ufe in their occupation, 

 (tabbed his companion about the region of the ftomach. On 

 opening the abdomen of the wounded man after his death the 

 food and medicines he had taken were in part found in the cav- 

 ity of the belly, on the outfide of the bowels ; and there was a 

 wound about half an inch long at the bottom of the ftomach ; 

 which I fuppofe was diftended with liquor and food at the time 

 of the accident j and thence was more liable ro be injured at its 

 bottom : but during the whole time he lived, which was about 

 ten days, he had no efforts to vomit, nor ever even complained 

 of being lick at the ftomach ! Other cafes fimilar to this are 

 mentioned in the philofophical tranfadions. 



Thus, if you vellicate the throat with a feather, naufea is pro- 

 ductd ; if you wound it with a penknife, ain is induced, but 

 not ficknefs. So if the foles of the fret of children or their arm- 

 pits are tickled, convulfive laughter is excited, which ceafet the 

 moment the hand is applied, to as to rub them more forcibly. 



The experiment therefore above related upon the lacleals of 

 a dead pig, which were included in a ftricl ligature, proves 

 nothing ; as it is not the quantity, but the kind of ftimulus, 

 which excites the lymphatic veiTels into retrograde motion. 



XI The Caufes which Induce the Retrograde Motions of Animal Vef- 

 fels ; and the medicines by 'which the Natural Motions are rejlored, 



1. SUCH is the conftru&ion of animal bodies, that all their 

 parts, which are fubjecied to lefs ftimuli than nature defigned, 

 perform their functions with lefs accuracy : thus, when too wa- 

 tery or too acefcent food is taken into the ftomach, indigeflion, 

 and flatulency, and heartburn fucceed. 



2. Another law of irritation, connate with our exiftence, is, 

 that all thofe parts of the body, which have previoufly been ex- 

 pofed to too great a quantity of fuch ftimuli, as ftrongly affect 

 thera, become for fome time afterwards difobedient to the nat- 

 ural 



