HISrORT of the SOClErr. 0.1 



The dodrine of the fympathy of the nerves has been fo 

 much employed in accounting for the effeds of opium, that Dr 

 Wilson judged it proper to make fome obfervations \ipon it ; 

 in which he endeavours to prove, that no fuch law of the ani- 

 mal oeconomy exifls ; and that all the phenomena, which have 

 been referred to. this fuppofed law, depend on certain changes 

 taking place in the Jenjorium commune. 



In an appendix, he relates fome experiments, made with a view 

 to determine the manner in which tobacco adls on living animals. 

 From thefe experiments it appears, that the fymptoms which 

 tobacco produces, when thrown into the heart, are the fame 

 with thofe excited by its immediate application to the brain. 

 That thefe fymptoms, when the tobacco is exhibited in the for- 

 mer way, proceed from no adion of the tobacco on the nerves 

 of the heart, but from its being conveyed along the aorta, and 

 immediately applied to the brain ; fince they do not follow its 

 injedion into the heart, when the aorta is previoufly fecured by 

 ligature ; although it was found, that interrupting the circula- 

 tion does not unfit the nervous fyftem from undergoing the 

 change neceflary for the produdion of fuch fymptoms. It alfo 

 appears from thefe experiments, that tobacco produces the fame 

 effeds, though more flowly, when thrown into the flomach and 

 inteftines as when thrown into the heart : That in the former 

 cafe, as in the latter, they are ftill to be afcribed to the tobacco 

 being received into the fanguiferous fyftem, and immediately 

 apphed to the brain ; and that the effeds of this drug, when it 

 ads merely on the nerves of the part to which it is applied, do 

 not elTentially diflFer from thofe of any ftrong topical irritation. 

 It may alfo be colleded from thefe experiments, that the pre- 

 fence of tobacco in the fyftem, like that of opium, only aflFei-ts 

 the irritability of the mufcles of voluntary motion, when it pro- 

 duces convulfions in them ; i. e. when it is apphed in confider- 



able 



