■^t2 ESSAYS AND OBSEHVATIONS 



from the brain,^ ta the parts to which it be- 

 longs J but docs not immediately deftroy the 

 power or influence remaining in the nerve it- 

 felf. Opium applied in lufficient quantity to 

 the fenfible parts of animals, not only quick- 

 ly puts a ftop to the fundion of the brain 

 and fpinal marrow, and thus produces in the 

 mufcles all the effeds of a ligature on their 

 nerves, but alfo deftroys tht power of every 

 nervous filament in the body (r)^ and there- 

 fore puts a flop to the motion of the heart 

 in frogs fooner than the deflruftion of the 

 brain and fpinal marrow. 



(t) The almoft inftantaneous palfy brought 

 on the hinder legs of a dog, by injeding a fo- 

 lution of opium into the cavity of its abdomen 

 (N*^ 22.), and the effeds of the fame folution 

 injeded into the flomach and guts of a frog 

 deprived of its heart (N° 2.), where no part 

 of the opiii7n could be conveyed to the muf- 

 cles, nor be conceived to alter the nature 

 of their gluten \ (hew, that the irritability 

 of the mufcles has not its feat in this ghie^ as 

 fome have lately imagined ^^. But if the 

 motions of irritated mufcles be owing to a 

 difagreeable fenfation excited in them or 



their 



* Aft. Gotdng. vol. ii. p. 152. 



