General Principles of Physiology. 103 



the heart has no nerves, and that all those which appear to 

 enter it are expended on the coats of the coronary arteries 

 without the fibres of the heart receiving a single thread*, an 

 opinion which far from removing all the difficulties only ren- 

 ders the influence of the passions on the motions of the heart 

 more inexplicable. These two authors maintain that the cardiac 

 nerves support and increase the irritability of the coronary 

 arteries ; but the existence of irritability in the arteries is still 

 doubtful t, and were it demonstrated it would be very strange 

 if irritability depended on the nervous influence in the arteries, 

 and in the heart, the most irritable of all organs, it were wholly 

 independent of this influence. 



M. Scarpa in his excellent work J on the nerves of the heart, 

 proves that they are as numerous, and distributed in the same 

 way as in other muscles. The opinion of this author, respecting 

 the power of the heart, is as much at variance with facts as the 

 opinions we have considered ; but he makes a very important 

 remark, that the insensibility of the heart, of which so much 

 has been said, and which has been regarded as a demon- 

 strative proof that the motions of the heart do not depend on 

 the nerves, proves only that the nerves of the heart are not of 

 the same kind with those of the muscles of voluntary motion, 

 and that the nervous power does not in them obey the same 

 laws §. 



This did not prevent Bichat|l from denying that the nervous 

 power has any share in the motions of the heart. This writer 



* Behreuds' Dissertatio qua Demonstrator Cor Nervis carere. Moguntia;, 

 1792, inserted in the third volume of the Collection of Ludwig. 



t This doubt has since been removed by experiments, which demon- 

 strate the excitability both of the larger arteries and the capillaries. The 

 reader will find an account of many experiments of this kind in the Intro- 

 duction to my Treatise on Symptomatic Fevers, and Dr. Hastings's Trea- 

 tise on Inflammation of the Mucous Membrane of the Lungs, 



J Tab. Muroloff. ad illust. Hist. Anat. Cardiucorum Nervorum, &c., Ti- 

 cini, 1794. § Jb. § 20. 



II Bichat. RecJierch. Phys. sur la Vie et la Mort. Paris, 1800. Part 2, 

 Art. 11, § 1. 



