MO TOR FUNCTIONS OF THE B ULBO-SA CRAL O UTFLO W 53 



nerves and form a single nerve (the pelvic nerve) on each side, 

 which passes direct to the bladder without dipping down into the 

 pelvis to join the lateral chain of ganglia (Fig. 5). 



The groups of cells on the bladder and rectum, with which 

 this pelvic nerve communicates, have received the title of hypo- 

 gastric plexus, which is misleading, as these cells have very little 

 to do with the hypogastric nerve and are chiefly concerned with 

 the pelvic nerve ; it is better therefore to discard this term and to 

 call this collection of nerve cells and nerve fibres the pelvic 

 plexus, as Langley has done. 



The great characteristic of the sacral outflow is that its motor 

 nerve cells supply with motor nerves the cloacal region of the 

 alimentary canal. In the cloacal region I include the large in- 

 testine and the bladder, for the origin of the bladder is from the 

 cloaca. There is no evidence whatever that the pelvic nerve ever 

 supplies any part of the small intestine, just as there is no evi- 

 dence that the vagus nerve ever supplies any part of the cloacal 

 region. 



In the large intestine there are, as in the rest of the intestine, 

 both circular and longitudinal muscles, and it has been taught, 

 especially by the Vienna school, that the motor nerve supply from 

 the sacral region was confined to the longitudinal muscles and 

 that the circular muscles were supplied from the lumbar splanch- 

 nics, the inhibitory nerves arising respectively from the opposing 

 region. Such a scheme of reciprocal innervation has been put 

 forward for all hollow organs possessing longitudinal and cir- 

 cular muscles, and in no case has it been established. Certainly 

 in the case under consideration it is not true. Bayliss and Star- 

 ling by means of theenterograph especially studied this question, 

 and proved that both sets of muscle contract when the pelvic 

 nerve is stimulated. Langley and Anderson confirm this observ- 

 ation and find indeed that the whole of the large intestine receives 

 its motor supply from the nerve cells belonging to the sacral out- 

 flow, with the exception of the internal sphincter ani, which, as 

 already mentioned, is supplied by cells belonging to the thor- 

 acico-lumbar outflow. Elliott has confirmed this by the injec- 

 tion of adrenalin, which causes no contraction whatever of any 

 part of the large intestine with the exception of the internal 

 sphincter ani. 



The musculature of the bladder is the remaining portion of 



