( 596 ) 



Exp. 15, VI. 1906. Emys orbicularis, Right nervus vagus. Non- 

 polarising electrodes. Charging currents. Capac. 0.2 microfarad. Number 

 of stimuli 10; (2 per second). Resting pauses between the series of 

 stimuli 2 minutes. Experimental animal in 0.6°/ Na CI solution, 

 heated to 28° C. 



Two particulars deserve notice : 



1. that the greatest retardation falls not in the second but in the 

 ili in I period. 



2. With stimulation with 7,61, 9,48, 13,83 ergs turbulent motions 

 occur in the ventricle, followed by the post-undulatory pause, namely 

 in the first systole after the preliminary retardation. 



The relation brought to light in both these cases might be explained 

 by assuming with Langley that the vagus fibres do not reach the 

 heart directly, but first pass a station of the intra-cardial ganglia. 

 If this be the case the stimulated condition of the prae-ganglionic 

 fibres will only be communicated to the post-ganglionic by contact 

 in the ganglion cells. But then the quantitative coercion of Weber's 

 law holds for these ganglion cells and a relation as sketched above 

 is not astonishing. To this conception may be objected that probably 

 with stimulation of the post-ganglionic fibres (in the so-called n. 

 coronarius l ) the same relation will be found in its principal features. 

 If on this point not only preliminary, but decisive experiments, will 

 have been made, it will be found that the just-mentioned explanation 



J) On the n. coronarius as a post-ganglionic nerve vide J. Gewin, 1. c. 



