General Principles of Physiology. 101 



clle the results of his experiments with the influence of the 

 nervous power over the motions of the heart, and in rejecting 

 this influence, finding- it impossible to explain the use of the 

 cardiac nerves and the effect of the passions on the heart. 

 Here is the great difficulty in the controversy of which we speak. 

 Those who, like Fontana, formally reject all intervention of 

 the nervous influence, have been forced to admit that the nerves, 

 destined to convey to every other part life, feeling, and motion, 

 have no known use in the heart *. 



Such consequences evidently disclose the insufficiency^ of 

 the theory of Haller, and several of his followers have acknow- 

 ledged the necessity of some modification of it, and admit the 

 nervous power to be one of the principles on which irritability 

 depends. They are thus enabled to assign a use to the nerves 

 of the heart, and to explain the influence of the passions on this 

 organ. But when they have attempted to explain why the in- 

 terruption ^of all communication between the brain and the 

 heart does not stop the motions of the latter, they have been 

 obliged to abandon the generally-received opinion, which re- 

 gards the brain as the only centre and source of nervous 

 power ; and admit, without any direct proofs, that that power 

 is generated throughout the whole extent of the nervous system, 

 even in the smallest nerves ; and that it can exist for a certain 

 time in the nerves of any part, independently of the brain. 

 Among the authors of this opinion the learned Professor Pro- 

 chaska is one of those who has given the best account of itt. 

 But when he applies it to the motions of the heart, and attempts 

 to explain why they are independent of the will, and yet in- 

 fluenced by the passions, his opinion appears undecided. He 

 has recourse to the ganglions, and hesitates what functions to 

 ascribe to them. Sometimes he considers them as knots, as 



* Mimoires sur les Parties Sensihl. et hritab., torn. III., p. 234. Sec 

 also Caldani, ibid. p. 471 ; et le Traitd sur le F'enin de la Viptre, torn. 11., 

 p. 169— 171. 



t Commentatio de Functionilms Syslemalis Nervosi, published in the third 

 fasciculus of the Annolationes Academ. of this writer, and reprinted at 

 Vienna in his Opera Minora, in 1800. 



