108 DR RUTHERFORD ON THE INFLUENCE OF THE VAGUS 



It has long been known that the movements of the heart may be influenced 

 by nerves connecting it with the cerebro-spinal axis. It is unnecessary, however, 

 that I should enter into a full historical account of this subject, inasmuch as this 

 has already been given at great length by Von Bezold. - I need, therefore, only 

 say that it is now perfectly ascertained that the nerves which convey influences 

 between the cerebro-spinal axis and heart are branches of the sympathetic and 

 vagus. The sympathetic filaments take origin in the brain and medulla 

 oblongata, pass through the cervical portion of the spinal cord, the last cervical 

 and first dorsal sympathetic ganglia, and from thence to the heart (M. and E. 

 Cyon).! These nerves convey to the cardiac organ influences which accelerate 

 its action. Von Bezold| thought he had proved that they are continually 

 prompting the heart to move ; he having observed that on dividing the cervical 

 portion of the spinal cord — wherein these nerves are contained — that the heart 

 beats more slowly than it does previous to the injury. He, however, omitted 

 to take into account the fact, that on dividing the cervical portion of the spinal 

 cord nearly all the blood-vessels of the body are paralysed, and that the lowered 

 bloocl-pressure which results therefrom may be the cause of the slower action 

 of the heart which follows the lesion. The brothers Cyon found, that although 

 retardation of the pulse follows division of the spinal cord, no such change is 

 usually observed if the cardiac motor nerves coming from the last cervical and 

 first dorsal ganglia are divided, although these same nerves are cut across when 

 the cervical portion of the spinal cord is divided. We have, therefore, no 

 reason whatever for supposing that these nerves are continually in action, but, 

 on the contrary, the evidence advanced by the brothers Cyon is entirely 

 opposed to such an idea. 



It has also been maintained by Von Bezold § and others, that cardiac motor 

 nerves are to be found in the trunk of the cervical sympathetic nerve. With 

 regard to this matter, I have performed many experiments on rabbits, and have 

 invariably failed to observe any excitement of the heart follow stimulation 

 of this nerve unless the irritant (electricity) was transmitted through the nerve 

 close to the inferior cervical ganglion. In that case accelerated cardiac action 

 often followed the irritation ; but such result is no proof that the trunk of the 

 cervical sympathetic contains motor nerves for the heart, seeing that the irritant 

 was applied to the nerve near enough to the inferior cervical ganglion to throw 

 into action the cardiac motor nerves derived from the spinal cord. I therefore 

 agree with Ludwig and Weinmann,|| in considering the cervical sympathetic as 

 not at all a cardiac nerve. 



* Von Bezold, Untersuchungen liber die Innervation des Herzens, l* 6 und 2 te Abtheilung. 

 Leipsic, 1863. 



t M. and E. Cyon, Rbichert and Du Bois Reymond's Arcliivs, 1867, p. 389. 



X Lib. tit. 2 te Abtheilung, pp. 230 and 257. § Lib. tit. 1 te Abtheilung, p. 147. 



|| L,udwig's Lehrbuch der Physiologie, ii ter Band, p. 178. 



