68 EFFECTS OF 



fail in its effects, since these must evidently 

 depend on the degree in which the circulation 

 is obstructed, and on the length of time during 

 which the obstruction is continued. 



There can then be little doubt that the woorara 

 affects the brain, by passing into the circulation 

 through the divided vessels.* It is probable, 

 that it does not produce its effects, until it enters 

 the substance of the brain, along with the blood, 

 in which it is dissolved ; nor will the experiments 

 of the Abbe Fontana, in which he found the 

 ticunas produce almost instant death when in- 

 jected into the jugular vein of a rabbit, be found 

 to militate against the conclusion, when we con- 

 sider how short is the distance, which, in so small 

 an animal, the blood has to pass from the jugular 

 vein to the carotid artery, and the great rapi- 

 dity of the circulation; especially in a rabbit 

 under the influence of powerful excitement, in 

 whom the heart cannot be supposed to act so 

 seldom as three times in a second. 



I have made no experiments to ascertain 

 through what medium other poisons operate 

 when applied to wounds; but from analogy, we 

 may suppose, that they also enter the circulation 

 through the divided blood vessels. 



IV. The facts already related, led me to con- 

 clude that alcohol, the essential oil of almonds, 

 the juice of aconite, the oil of tobacco, and the 



* See Additional Note F. 



