550 THE URINARY APPARATUS [CH. XXXVI. 



lower dorsal and upper lumbar nerves ; these fibres pass to the 

 sympathetic chain, from here to the inferior mesenteric ganglion, 

 and ultimately reach the bladder by the hypogastric nerves. Stimu- 

 lation of these nerves causes contraction of the circular fibres of the 

 bladder, including the sphincter; (2) from the second and third 

 sacral nerves; these run to the bladder by the nervi erigentes. 

 Stimulation of these nerves causes relaxation of the sphincter and 

 contraction of the detrusor urinse. (Zeissl.) Langley and Anderson 

 find, however, that stimulation of both sets of nerves causes contrac- 

 tion of both longitudinally and circularly arranged muscle bundles. 



