WORK UPON VISCERAL AND ALLIED NERVES. 65 



on the course of the dilator fibres are placed in the solar 

 plexus and renal ganglia. 



T/ie bladdej\ — When considering the innervation of 

 this viscus we have again to note that we are dealing with 

 one which, as commonly described, possesses a double 

 muscular wall and a double nerve supply, an upper one 

 from the lumbar nerves and a lower from the sacral via 

 the nervi erigentes. With regard to the question of the 

 reversed function of the two sets of fibres on the two 

 muscular coats (v. Brisch's theory), we have evidence 

 leading to a similar conclusion as in the case of the colon. 

 Thus Griffiths ^ brings evidence of an anatomical nature 

 that in reality we have to deal with a viscus possessing a 

 single muscular wall. Zeissl,"' on the contrary, argues from 

 his experiments that the sacral set cause, when stimulated, 

 contraction of the detrusor urinae and inhibition of the 

 sphincter, and that the hypogastrics cause contraction of 

 the sphincter and inhibition of the detrusor urinse, though 

 the evidence of this last action he does not consider very 

 satisfactory. Langley and Anderson, however, take the 

 opposite view, and consider that the interpretation which 

 Zeissl has placed upon his results is not the correct one. 

 Their experiments show that stimulation, of both the 

 hypogastric and pelvic (nervus erigens) nerves, causes 

 contraction of both longitudinally and circularly arranged 

 muscle bundles. 



In reviewing the experiments of those who have been 

 working in recent years upon the origin and course of 

 fibres which innervate the bladder, we may first notice 

 those of Navrocki and Skabitschewski," who worked upon 

 curarised dogs, and observed the movements of the bladder 

 directly by the naked eye. This method they chose as the 

 only one giving certainly reliable results, for they found that 

 the introduction of a catheter, or tying in a tube into the 

 apex of the bladder, led to irregular contractions, which 

 tended to make results by such methods unreliable. The 



"^ Journ. of Anat. and Phys., vol. xxv., p. 535, 1891. 

 ^ Pfluger's Archiv, vol. liii., p. 560, 1893. 

 ^ Ibid., vol. xlviii., p. 335, 1891. 



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