474 PHYSIOLOGY CHAP. 



As regards the central organs on which the movements of the 

 bladder depend, it can be gathered from the above that there must 

 be cerebral, spinal, and sympathetic centres : the first come into 

 play in voluntary micturition and that excited by the feeling of 

 vesical tension ; the second in involuntary and purely reflex 

 micturition ; the third in the micturition which can be experi- 

 mentally produced after cutting off all connections of the two 

 former with the bladder. 



With what part of the cerebrum do we act in voluntary 

 retention of urine, when the tone of the vesical sphincter is 

 increased, and in micturition, when that muscle is voluntarily 

 relaxed ? To this we are unable to give any adequate reply. 

 We only know from Budge's early work that it is possible by 

 electrical stimulation of the cord to follow the spinal paths from 

 the bladder to the brain, as far as the cerebral peduncles. 

 We also know from the early work of Valentin that excitation 

 of different parts of the brain, especially of the cerebral 

 peduncles, the corpora striata, and the optic thalami, provoke 

 movements of the bladder. Certain experiments of Mosso and 

 Pellacani indicate that the cerebro-vesical paths run in the 

 posterior segment of the cord. Lastly we know from Bechterew 

 and Mislawski that electrical excitation of the sygmoid gyrus of 

 the cerebral cortex of dogs, behind the external extremity of the 

 sulcus cruciatus, produces contraction of the detrusor vesicae. 

 Sherrington also found a cortical centre for the bladder in 

 monkeys. 



In man, according to the observations of Friedmann (1904), 

 who saw in a child that a circumscribed cortical lesion produced 

 an almost isolated disorder of the voluntary innervation of the 

 bladder, the cortical centre for the latter lies at the limit of the 

 upper third of the posterior central convolution, in the direct 

 contiguity of the upper parietal lobe. The centre for the arm is 

 located immediately in front of it. The same conclusion appears 

 also from the work of Czyhlarz and Marburg. 



As regards the localisation of the spinal centres for the bladder, 

 Budge (1858) discovered in the spinal cord of rabbits a spot a few 

 millimetres in extent, which he termed the genito-spinal centre ; 

 this controls the contractions of the bladder, lowest part of the 

 intestine, and the vasa deferentia. In dogs, on the contrary, 

 Giannuzzi (1863) found two points in the lumbar cord which, if 

 mechanically excited by a deep puncture, react by contractions of 

 the bladder ; the first point corresponds with the level of the third, 

 the second with that of the fifth lumbar vertebra. There is no 

 doubt that the lumbar - sacral cord contains all the central 

 mechanisms both for the periodic emission and the retention of 

 urine. This is proved by the experiments of Goltz (1874) on dogs 

 whose cord was divided between the last dorsal and the first 



