ACTION OF VEGETABLE POISONS. 303 



In consequence of the extreme distension of the heart, this 

 could not be done without irritating the fibres with the 

 point of the scalpei. Immediately both auricles and ven- 

 tricles began to contract with considerable force, so as to re- 

 store the circulation. Artificial respiration was produced, 

 and the circulation was kept up for more than half an hour, 

 beyond which time the experiment was not continued. 



We may conclude from these experiments, that the effect It destroys the 

 of the infusion of tobacco, when injected into the intestine of j^^^'^^^^ * ^ 

 a living animal, is to destroy the action of the heart, stop- 

 ping the circulation and producing syncope. It appeared to 

 me, that the action of the heart ceased, even before the ani- 

 mal had ceased to respire; and this was confirmed by ano- 

 ther experiment, in which, in a dog killed by the infusion 

 of tobacco, I found tlie cavities of the left side of the heart 

 to contain scarlet blood, while in those of the right side the 

 blood was dark coloured. This poison therefore differs ir;u'« 

 terially from alcohol, the essential oil of almonds, and the 

 juice of aconite, which have no direct influence on the action 

 of the heart. The infusion of tobacco renders the heart in- 

 sensible to the stimulus of the blood, but it does not altoge- 

 ther destroy the power of muscular contraction, since the 

 heart resumed its action in one instance on the division of 

 the pericardium ; and I have found, that the voluntary mus- 

 cles of an animal killed by this poison are as readily stimu- 

 lated to contract by the influence of the Voltaic battery, as 

 if it had been killed in any other manner. At the same arid aUw of the 

 time, however, that the infusion of tobacco destroys the ac- 

 tion of the heart, it appears to destroy also the functions of 

 the brain, since these did not return in the last experiment; 

 although the circulation was restored, and kept up by artifi- 

 cial respiration. 



Since there is no direct communication between the intes- Its absorptioik 



tinal canal and the heart, I was at first induced to suppose, ^^ ^'"^ ^'*^'* 

 _ , . PI quescionibb. 



that the latter becomes affected in consequence of the infu- 

 sion being conveyed into the blood by absorption. Some 

 circumstances in the following experiment have since led 

 ipe to doubt, whether this is the case. 



Exp. 12. In a dog, whose head was removed, I kept up Exp. 12, 

 the circulation by means of artificial respiration, in the man- 

 ner 



