There appears, indeed, to be a special and intimate connection between the explosion of sexual detumescence and the explosive energy of the bladder; so that they may reinforce each other and to a limited extent act vicariously in relieving each other's tension. It is noteworthy that nocturnal and diurnal incontinence of urine, as well as "stammering" of the bladder, are all specially liable to begin or to cease at puberty. In men and even infants, distention of the bladder favors tumescence by producing venous congestion, though at the same time it acts as a physical hindrance to sexual detumescence[49]; in women--probably not from pressure alone, but from reflex nervous action--a full bladder increases both sexual excitement and pleasure, and I have been informed by several women that they have independently discovered this fact for themselves and acted in accordance with it. Conversely, sexual excitement increases the explosive force of the bladder, the desire to urinate is aroused, and in women the sexual orgasm, when very acute and occurring with a full bladder, is occasionally accompanied, alike in savage and civilized life, by an involuntary and sometimes full and forcible expulsion of urine.[50] The desire to urinate may possibly be, as has been said, the normal accompaniment of sexual excitement in women (just as it is said to be in mares; so that the Arabs judge that the mare is ready for the stallion when she urinates immediately on hearing him neigh). The association may even form the basis of sexual obsessions.[51] I have elsewhere shown that, of all the influences which increase the expulsive force of the bladder, sexual excitement is the most powerful.[52] It may also have a reverse influence and inhibit contraction of the bladder, sometimes in association with shyness, but also independently of shyness. There is also reason to suppose that the nervous energy expended in an explosion of the tension of the sexual organs may sometimes relieve the bladder; it is well recognized that a full bladder is a factor in producing sexual emissions during sleep, the explosive energy of the bladder being inhibited and passing over into the sexual sphere. Conversely, it appears that explosion of the bladder relieves sexual tension. An explosion of the nervous centers connected with the contraction of the bladder will relieve nervous tension generally; there are forms of epilepsy in which the act of urination constitutes the climax, and Gowers, in dealing with minor epilepsy, emphasizes the frequency of micturition, which "may occur with spasmodic energy when there is only the slightest general stiffness," especially in women. He adds the significant remark that it "sometimes seems to relieve the cerebral tension,"[53] and gives the case of a girl in whom the aura consisted mainly of a desire to urinate; if she could satisfy this the fit was arrested; if not she lost consciousness and a severe fit followed.