52 EFFECTS OF 



and some minutes elapsed before they had en- 

 tirely ceased. 



In this experiment, the disposition to contrac- 

 tion in the muscles was very much increased, 

 instead of being diminished, as in those before 

 related. If the infusion of tobacco influences the 

 heart merely from being absorbed into the blood, 

 and thus coming into actual contact with its 

 fibres, there is no evident reason why the removal 

 of the brain, and the employment of artificial re- 

 spiration, should occasion so material a difference 

 in its effects. If the contractions of the volun- 

 tary muscles had depended on the infusion 

 circulating with the blood, it is reasonable to 

 suppose that the pressure on the aorta would 

 have occasioned some diminution of them, and 

 that the complete obstruction of the circulation 

 would have caused them to cease altogether. 



From these considerations, I am induced to 

 believe that the infusion of tobacco, when in- 

 jected into the intestines, influences the heart 

 through the medium of the nervous system ; but 

 I have not been able to devise any experiment 

 by which the truth or fallacy of this opinion 

 might be put beyond the reach of doubt. 



It appears remarkable, that the brain and 

 nervous system, although not necessary to the 

 action of the heart, should, when under the 

 influence of the infusion of tobacco, be capable 

 of acting on this organ so as to stop its action ; 

 but this is analogous to what occurs in conse- 

 quence of violent emotions of the mind. Those 



