238 DISTRIBUTION OF NERVES, ETC., IN BLADDER OF FROG. 



sion and subdivision of dark-bordered fibres. But 

 whether the large dark-bordered fibres seen in the 

 nerve-trunks pass directly to their distribution in the 

 bladder, or in the first place become connected with 

 ganglion-cells, it is difficult to decide with absolute 

 certainty ; I have, however, traced several of the 

 large dark-bordered fibres directly from the trunks to 

 their distribution, but even in these instances I am 

 not prepared to assert that no branches pass to the 

 ganglion- cells. My impression is that many of the 

 fibres do so, but that some pass to their distribution 

 without being connected with ganglion- cells. I think 

 it probable that, of the fibres resulting from the 

 division of a dark-bordered fibre derived from the 

 spinal cord, some may become connected with the 

 ganglion- cells above referred to, while others pass to 

 their distribution in the bladder without being con- 

 nected with these cells. 



In the very thin membrane of which the walls of 

 the frog's bladder -are composed we may follow out 

 the distribution of nerves a, to the muscular tissue, 

 6, to the surface of the mucous membrane, c, to the 

 vessels, and d, to the connective tissue. There is a 

 network ramifying on the outer surface, from which 

 fibres pass to supply all the tissues of the bladder. 



The muscular fibre- cells of the bladder itself and 

 of the small arteries are crossed sometimes in two or 

 three places by very fine nerve-fibres ; and not un- 

 f requently the nerve-fibre runs parallel with the mus- 

 cular fibre-cell for some distance. Fig. 1, PL V, p. 217. 



Some of the most recent drawings of this form of 

 muscular tissue and the supposed arrangement of its 

 nerves are very defective. J. Arnold, in his article on 

 organic muscle in Strieker's "Anatomy," has given 

 some not very satisfactory drawings of the muscular 

 tissue from the frog's bladder. His figures on page 

 142, are evidently taken from bundles of muscular 

 fibres. The delicate cells, isolated ready for obser- 



