"228 On the Innervation of the Mammalian Heart. [May 10, 



is well known, very slight stimulation with a Faradaic current 

 destroys the activity of the ventricle by bringing about a peculiar con- 

 dition of fibrillar contractions. 



The author's procedure was as follows : The ventricular nerves pass 

 on to the ventricle at definite points of the auricular ventricular 

 boundary, where they are collected into larger trunks. He has 

 observed that division of these trunks has no influence on the rhythm 

 of the heart, nor does it in any way impair the action of the vagus or 

 accelerans nerve. These ventricular nerves are therefore not essential 

 to any of these processes. 



The ventricular nerves are the continuation of certain definite 

 cardiac nerves, which can be isolated in the thorax at a distance from 

 the heart. When these cardiac nerves are stimulated, some of the 

 ventricular nerves must be stimulated too. In particular, the majority 

 of the nerves on the posterior surface of the heart, are derived from a 

 trunk which arises either from the left vagus gauglion, or from some 

 part of the Ansa Vieusseni. This nerve usually runs quite isolated 

 to the heart. The result of stimulation of the peripheral end of this 

 nerve are as follows : — 



Out of 14 experiments, it exerted in 4 a vagus action, without any 

 acceleration ; in 2 an acceleratory action without any inhibitory ; in 

 8 it had no influence on the rhythm. The nerve sometimes gives off: 

 obvious branches to the auricle ; in some of the cases where no 

 influence on the rhythm was produced, these had been cut away. 

 Particular attention was given to this nerve, because it is easy to 

 isolate, and because it certainly contains fibres which go on to the 

 ventricle. 



The author also stimulated the other cardiac branches, which are 

 in obvious connexion with the ventricular nerves. Sometimes they 

 produced inhibition, sometimes acceleration, but also in this case the 

 division of the trunks which continue these nerves on to the ventricle 

 did not produce any change in the result of their stimulation. The 

 author from the above observations concludes that the ventricular 

 nerves have no direct influence on the rhythm of -the heart. 



Stimulation of the central end of those cardiac nerves, which are 

 continued on to the ventricle, is. followed by marked reflex phenomena ; 

 and this fact, in conjunction with the negative result just recorded, 

 leads the author to regard the ventricular nerves as being chiefly 

 sensory, or more exactly, centripetal. 



The reflex phenomena are, rise and fall of blood pressure, slowing 

 and quickening of the pulse. On placing a small piece of blotting 

 paper soaked in acetic acid on to the surface of the ventricle in the 

 rabbit, a rise of blood pressure was observed ; the acetic acid was 

 moderately strong ; a second application to the same part had no 

 effect. On tearing- through the nerve trunks from which the ven- 



