OF THE BLADDER AND PROSTATE. 
29 
bears upon the true structure of the sphincter vesicee, which has up till the present been 
regarded as consisting of circular fibres instead of two sets of very oblique spiral fibres 
intersecting each other at two fixed points, those points corresponding to the right and 
left aspects of the cervix. 
I have chosen to speak of anterior and posterior looped fibres, but this description, as 
will readily be perceived, is purely arbitrary, the fibres which begin on the posterior 
surface curving round and crossing each other anteriorly and the reverse. The method 
followed has been suggested by the direction and the crossing of the fibres, as well as by 
the position of the fibres in the parietes ; it so happening that those portions of the 
fibres which form the terminal loops occupy a deeper situation than that occupied by 
the same fibres where they cross. By considering the fibres as anterior which cross 
anteriorly, and vice versa, we are enabled to compare and contrast the direction of the 
fibres on the anterior, posterior, and lateral aspects of the bladder without in any way 
obscuring or interfering with their continuity. As it is to the direction pursued by the 
fibres that we must look for an explanation of the manner in which the bladder contracts, 
the plan adopted has many advantages, 
The anterior and posterior fibres of the third layer, whose upper terminal loops spread 
out on the upper third of the bladder anteriorly and posteriorly, and whose lower 
terminal loops converge to assist in the formation of the sphincter, form two twisted 
slings (Plate III. fig. 8, h g, o q), the influence exercised by which in dragging the summit 
of the bladder towards the cervix or fixed point must be very considerable. The anterior 
and posterior sets of fibres which spread out on the summit, in addition to being con- 
tinuous upon themselves to form loops, are continuous with each other on the upper 
third of the lateral aspects of the bladder. In these situations they unite with con- 
siderable regularity, after the manner of a groined arch (Plate III. fig. 6, q l), so that 
they form a kind of hood or capsule, which envelopes the apex. The fibres of the 
anterior and posterior sets interchange slightly with the fibres which are above and 
beneath them. 
Two sets of fibres corresponding in their essential features to the anterior and 
posterior sets of fibres just described, may by a little careful examination be detected on 
the sides of the viscus. The fibres in question are feebly developed when compared 
with the anterior and posterior ones ; but their distribution and general configuration is 
the same. Thus, if we trace the fibres from the median line intersecting the left half 
of the bladder, we shall find that they wind round anteriorly in a downward spiral direc- 
tion, and cross that which intersects the right half at a point nearly midway between 
the apex and fundus (Plate III. fig. 9, qrh g). Pursuing their downward spiral course, 
they curve round the left side of the fundus, and reverse their direction to reappear on 
the right side. They then proceed in an upward spiral direction, recross the mesial 
line of the right side, and curve round until they regain that on the left, thus com- 
pleting the figure of eight. These two sets of lateral fibres spread out on the anterior and 
posterior aspects of the upper third of the bladder, their terminal loops confining them- 
