SUMMARY OF THE PNEUMOGASTRICS. 251 



a few exceptional cases occur in which these effects are not 

 observed. 



The facts just mentioned are exceedingly interesting in 

 connection with the experiments of Traube upon the action 

 of digitalis after section of the pneumogastrics. It will be 

 remembered that, in these experiments, digitalis failed to 

 diminish the number of beats of the heart when the nerves 

 had been divided in the neck, showing that the separation 

 of the heart from its connections with the cerebro-spinal 

 system removed the organ from the peculiar and character- 

 istic effects of the poison. 1 



It would be interesting to determine whether the pneu- 

 mogastrics influence the intestinal secretions through their 

 own fibres or through filaments received from the sympa- 

 thetic system; but there are no experimental facts suffi- 

 ciently definite to admit of a positive answer to this question. 

 If the action take place through the sympathetic system, as 

 in the case of the stomach, the filaments of communication 

 join the pneumogastrics high up in the neck, and become 

 incorporated with the true fibres of the nerve in its trunk. 



Summary of the Distribution, Properties, and Functions 

 of the Pneumogastrics. The pneumogastrics have their ap- 

 parent origin from the lateral portion of the medulla oblon- 

 gata, just behind the olivary bodies, between the roots of 

 the glosso-pharyngeals and the spinal accessories. Their 

 deep origin is mainly from the gray substance in the floor 

 of the fourth ventricle. In their course, they each present 

 two ganglia, the ganglion of the root and the ganglion of the 

 trunk. They pass out of the cranial cavity on either side, by 

 the posterior foramen lacerum, with the glosso-pharyngeals, 

 the spinal accessories, and the internal jugular veins. 



The nerves receive anastomosing branches from the spinal 

 accessories, facials, sublinguals, the anterior roots of the up- 

 per two cervicals, and the sympathetic. The nerves fre- 



1 See p. 224. 



