io DEFINITIONS. SECT. II. 2, 



through thefe glands, and having fuffered feme 

 change in them, are carried forward into the blood, 

 and lupply perpetual nourifhment to the fyftem, or 

 replace its hourly wafte. 



8. The ftomach and inteftinal canal have a con- 

 flant vermicular motion, which carries forwards 

 their contents, after the la&eals have drank up the 

 chyle from them -, and which is excited into aclion 

 by the ftimulus of the aliment we fwallow, but 

 which becomes occafionally inverted or retrograde, 

 as in vomiting, and in the iliac paffion. 



II. i. The wordfen/brium in the following pages is 

 deligned to exprefs not only the medullary part of 

 the brain, fpinal marrow, nerves, organs of fenfe, 

 and of the mufcles ; but alfo at the fame time that 

 living principle, or fpirit of animation, which re- 

 iides throughout the body, without being cogniza- 

 ble to our fenfes, except by its effects. The changes 

 which occafionally take place in the fenforium, as 

 during the exertions of volition, or the fenfations 

 of pleafure or pain, are termed fen/or ial motions. 



2 The fimilarity of the texture of the brain to 

 that of the pancreas, and fome other glands of the 

 body, has induced the inquirers into this fubject to 

 believe, that a fluid, perhaps much more fubtile 

 than the eleclric aura, is feparated from the blood 

 by that organ for the purpofes of motion and fenfa- 

 tion. When we recollect, that the eleclric fluid it- 

 ielf is actually accumulated and given out volunta- 

 rily by the torpedo and the gymnotus ele&ricus, 

 that an electric (hock will frequently ftimulate into 

 motion a paralytic limb, and laftly that it needs no 

 perceptible tubes to convey it, this opinion feems 

 not without probability ; and the fingular figure of 

 the brain and nervous fyftem feems well adapted to 

 dHiribute it over every part of the body. 



For the medullary fubftanceof the brain not only 

 occupies the cavities of the head and fpine, but pat 



ics 



