In the woman the specifically sexual muscular process is less visible, more obscure, more complex, and uncertain. Before detumescence actually begins there are at intervals involuntary rhythmic contractions of the walls of the vagina, seeming to have the object of at once stimulating and harmonizing with those that are about to begin in the male organ. It would appear that these rhythmic contractions are the exaggeration of a phenomenon which is normal, just as slight contraction is normal and constant in the bladder. Jastreboff has shown, in the rabbit, that the vagina is in constant spontaneous rhythmic contraction from above downward, not peristaltic, but in segments, the intensity of the contractions increasing with age and especially with sexual development. This vaginal contraction which in women only becomes well marked just before detumescence, and is due mainly to the action of the sphincter cunni (analogous to the bulbo-cavernosus in the male), is only a part of the localized muscular process. At first there would appear to be a reflex peristaltic movement of the Fallopian tubes and uterus. Dembo observed that in animals stimulation of the upper anterior wall of the vagina caused gradual contraction of the uterus, which is erected by powerful contraction of its muscular fiber and round ligaments while at the same time it descends toward the vagina, its cavity becoming more and more diminished and mucus being forced out. In relaxing, Aristotle long ago remarked, it aspirates the seminal fluid. Although the active participation of the sexual organs in woman, to the end of directing the semen into the womb at the moment of detumescence, is thus a very ancient belief, and harmonizes with the Greek view of the womb as an animal in the body endowed with a considerable amount of activity,[117] precise observation in modern times has offered but little confirmation of the reality of this participation. Such observations as have been made have usually been the accidental result of sexual excitement and orgasm occurring during a gynæcological examination. As, however, such a result is liable to occur in erotic subjects, a certain number of precise observations have accumulated during the past century. So far as the evidence goes, it would seem that in women, as in mares, bitches, and other animals, the uterus becomes shorter, broader, and softer during the orgasm, at the same time descending lower into the pelvis, with its mouth open intermittently, so that, as one writer remarks, spontaneously recurring to the simile which commended itself to the Greeks, "the uterus might be likened to an animal gasping for breath."[118] This sensitive, responsive mobility of the uterus is, indeed, not confined to the moment of detumescence, but may occur at other times under the influence of sexual emotion.