vin THE EXCEETIOX OF UEIXE 473 



from the urethra, produced artificially by surcharging the bladder 

 with fluid, while a pressor effect upon the bladder walls seldom 

 makes its appearance. 



In a second set of experiments (1894), von Zeissl, experiment- 

 ing not with curarised dogs, but on such as were merely under 

 morphine, obtained results which were wholly in agreement with 

 the preceding. He also performed a new series of experiments to 

 determine the reflexes of the sphincter and detrusor, by excitation 

 of the central end of certain sensory nerves (sciatic, ulnar, median, 

 phrenic, splanchnic, and vagus). The method employed was 

 simpler than the above. In curarised male dogs he introduced a 

 glass tube right into the bladder, or to the end of the membranous 

 urethra, according as he wished to bring out the effect on the 

 detrusor, or the sphincter. 



This tube was brought into direct connection with a water 

 manometer, which recorded on a revolving cylinder the flow from 

 the bladder consequent on excitation of the nerve. The peri- 

 toneum was not opened. 



Stimulation of the central end of the above nerves always 

 produced contraction of the detrusor and expansion of the 

 sphincter. The sole exception is the stimulation of the central 

 end of the vagus, which has no effect on the bladder, while, like 

 the other nerves, it causes a rise of arterial pressure. From this 

 we may conclude that the vesical reflexes produced by excitation 

 of the sensory nerves are transmitted by the motor paths in the 

 anterior sacral roots, which make up the nervi erigentes. 



The later work of Courtade and Guyon (1896), while it mainly 

 confirms von Zeissl's results, has little intrinsic value, since it was 

 carried out by a less perfect method, and under conditions farther 

 removed from the physiological. 



The more extensive researches of Langley and Anderson (1896), 

 on the innervation of the viscera, do, on the contrary, confirm 

 both the results of Nawrocki and Skabitschewsky, and those of 

 von Zeissl, which are also sustained by the later experiments of 

 Rehfisch and Wlassoff (1900). 



Von Zeissl afterwards (1902) continued his researches on the 

 innervation of the bladder, using the same method as before. He 

 found that central stimulation of the sciatic (even when all 

 increase of pressure in the bladder was excluded) induced partial 

 evacuation by opening the sphincter, which, however, might be due 

 solely to the nervi erigentes. If water is made to flow continuously 

 through the urethra central stimulation interrupts the flow, even 

 after the hypogastrics have been divided. This, ho\vever, is due, 

 not to the erigentes, but to the nerves which supply the striated 

 sphincters (external sphincter, compressor urethrae), the endings of 

 which, like those in the sphincter ani, are only paralysed by an 

 excess dose of curare. 



