298 ENDOCRINE GLANDS 



sympathetic and the vagus. The exact anatomical limit of 

 the true sympathetic control of the stomach corresponds 

 to the cardiac notch. 



As regards the control of the sphincters of the bladder 

 and of the urethra it is easy to understand, if we remember 

 that the bladder and the urethra come from the vesico 

 urethral portion of the urogenital sinus, itself part of the 

 cloaca, which is made of a portion of the terminal intes- 

 tines. We also know that the cloaca, in the process of 

 evolution, divides itself into an intestinal part (coprodeum) 

 and a urinary part (urodeum). The bladder and urethra 

 on one side, the colon and anus on the other are, therefore, 

 parallel derivatives of the same origin and it is only 

 natural that the enervation of these two systems should 

 be the same. 



As far as the large intestine is concerned, we know that 

 from the excito-motor point of view it is enervated by the 

 pelvic plexus and the excito motor enervation of the smooth 

 muscle sphincter is controlled by the true sympathetic; 

 it is, therefore, natural that the sphincters of the bladder 

 and urethra should be stimulated by the true sympathetic 

 and the rest of the musculature by the pelvic plexus. 



As regards the urethra and the genital organs, the 

 sympathetic enervation has an entirely different cause 

 which is easily understood if we know that this system 

 controls the smooth muscle fibres of the system derived 

 from the canals of Wolff and Muller. 



There are two other important points to take into 

 consideration, namely, the effect of the stimulation of the 

 sympathetic on metabolism and the phenomenon of inhi- 

 bition on the active contraction of certain smooth muscles 

 due to stimulation by the vagus or pelvic plexus. 



As far as stimulation of the sympathetic on metabolism 



