203 RETROGRADE Sect. XXIX. n. r. 



could 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 

 unwritable orlifelefs ; but this however is certain, that it is not 

 any quantity of any ftimulus, which induces the vefieis 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 lhoemakers quarrelled, 

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

 flubbed 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 ; and thence was more liable to be injured at its 

 bottom : but during the whole time he lived, > was abov.t 



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

 being fick at the ftomach ! Other cafes fimilar to this are men- 

 tioned in the philofophical tranla£tions. 



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

 duced ; if you wound it with a penknife, pain is induced, but 

 not ftcknefs. So if the foles of the feet of children or their arm- 

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

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



The experiment therefore above related upon the lacleals of 

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

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

 which excites the lymphatic veilels into retrograde motion. 



XL The Canfes luhich induce the Retrograde Motions of Animal Vef~ 

 fels ; and the Medicines by which the Natural Motions arc rejlored. 



i. Such is the conftruclion of animal bodies, that all their 

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

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

 tery or too acefeent food is taken into the ftomach, indigeftion, 

 and flatulency, and heartburn lucceed. 



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

 t!i;it all thofe parts of the body, which have previously been ex- 

 poled to loo >/' cat a quantity of iuch ftimuli, as ftrongly affect 



m, become for fomc time afterwards difobedient to the nat- 

 ural 



