General Principles of Physiology . 105 



fibre, and independent of the nervous influence, the circulation 

 in acephalous animals and the different pheenomena observed 

 in the experiments alluded to, present nothing that is not 

 easily understood ; but the use of the nerves of the heart, and 

 the influence of the passions on that organ become inexpli- 

 cable. The necessity of removing these difficulties has pro- 

 duced two parties among the supporters of irritability. The 

 one zealous favourers of the doctrine of pure irritability called 

 to their aid the most improbable hypotheses, and all their 

 efforts have only served to prove how difficult it is to support 

 the cause they espouse. The other confounded the nervous 

 power with irritability, which they consider as one of the func- 

 tions of that power ; but they have been obliged to admit, 

 either with respect to the seat or the mode of existence of the 

 nervous power, conditions, which by their own confession are 

 far from being demonstrated, respecting which they are not 

 agreed, and which in the application they make of them to the 

 motions of the heart, either do not wholly remove the old diffi- 

 culties, or create new ones." 



Such is the very accurate account of the state of our know- 

 ledge respecting the nature of the power of the heart, and the 

 relation which subsists between it and the nervous system 

 given by the Committee of the Royal Academy of Sciences, at 

 the time when M. le Gallois discovered that, by crushing the 

 spinal marrow, the power of this organ is so enfeebled that it 

 can no longer propel the blood ; from which, compared with 

 the fact that the power of the heart continues after the 

 removal of the brain, he inferred that it is derived from 

 the spinal marrow *. He thus explains the use of the cardiac 

 nerves, and why the heart is affected by the passions, the spinal 

 marrow being under the influence of the brain ; why the circu- 

 lation continues in acephalous animals ; and why we do not 

 destroy the power of the heart by removing the brain. M. le 

 Gallois' experiments were repeated with the same results in 



* M. le Gallois sur le Principe de la Vie Notamment mr cclui dcs 

 Mouvemcru du Caur et sur le Siege de ce Principe. 



