On the Agency of Nerves. 271 



own, as proving that the nervous influence is capable of acting as 

 a sedative to the heart and vessels of circulation, even to such a 

 degree as to destroy their power ; — and in another place he states 

 it as the result of many experiments, that '* suddenly crushing 

 any considerable portion of the brain or spinal marrow instantly 

 destroys the power of the heart." 



In various passages of his work, he speaks of the power of 

 the heart being impaired by various causes acting on the nervous 

 system ; for example, at p. 88. It is obvious, therefore, that 

 the opinion of the vital power of the heart being liable to dimi- 

 nution from causes acting on the nervous system, is one which 

 I share with Dr. Wilson Philip himself ; and the only difference 

 of opinion is in regard to the question, whether its power may 

 be increased by such causes, which is really of less consequence, 

 because if the vital power of the heart and of other muscles 

 may be increased in this manner, as I think it may, it is but 

 seldom that this kind of effect on it is produced. 



Dr. Philip found in different experiments, that the action of 

 the heart might be much affected by various agents, applied to 

 the nervous system, to which he gave the name of stimuli^ for 

 example, by spirits of wine applied to the brain or spinal marrow. 

 The account which he gave of the operation of these agents 

 was, that they increased the ordinary action of the heart, which 

 was going on at the time when they were applied, (Experiments 

 14, 15, 34, 36, 38, 41, 42,43, and p. 245.) The effect of these 

 appeared to me to be an increase of the contractile power of the 

 heart, rather than the application of a direct stimulus to it, 

 such as the prick of a pin on its muscular substance ; and to 

 be directly opposed to the effect of other agents (for example, 

 of tobacco,) which manifestly, and by Dr. Philip's own admis- 

 sion, diminish the contractile power of the heart. Dr. Philip 

 objects strongly to this way of expressing the result of these 

 experiments, and in opposition to it states a fact of which a 

 confess I was not aware, 'that the effect is produced by the spirits 

 of wine, although the heart is completely emptied of blood. 

 If by this he means, that when the heart is emptied of blood, 

 and completely quiescent^ the application of spirits of wine to 



