HISTOR Y OF THE INVOL UNTAR Y NER VO US S YSTEM 2 5 



CE 



. 5. THE DISTRIBUTION OF THE CONNECTOR FIBRES (BLACK) AND EXCITOR 

 NEURONS (RED) OF THE BULBO-SACRAL OR ENTERAL SYSTEM. 



The vagus nerve, V., contains the connector nerves of the excitor neurons of 

 the main viscera as far as the ileo-colic sphincter, I.C.S. The motor neurons all lie 

 on the organs themselves. 



The pelvic nerve, P., contains the connector fibres of the sacral outflow and 

 connects with peripheral excitor neurons on the large intestine and bladder. 



The vagus nerve thus contains the connector neurons to the motor cells of the 

 heart, H., which have to do with the slow wave-like contraction which is only found 

 in certain tortoises, such as Emys Europea, and does not appear to exist in higher 

 forms. The vagus nerve also contains the connector fibres to the excitor neurons on 

 the bronchi in the lung, Lu., and also the connector fibres to the excitor neurons on 

 the gall bladder and bile duct lying on the liver, LI. : it also contains the connector 

 fibres to the excitor neurons of the oesophagus, (E., the stomach, St., and the small 

 intestine, S.I., which here lie between the muscle layers in Auerbach's plexus. 



The pelvic nerve, P., which arises from the three sacral roots, S. i, 2 and 3, 

 contains the connector fibres to the excitor neurons of the large intestine, LI., and 

 also the connector fibres of the excitor neurons of the body of the bladder, B. 



