Up to the point to which we have so far considered it, the process of detumescence has been mainly nervous and vascular in character; it has, in fact, been but the more acute stage of a process which has been going on throughout tumescence. But now we reach the point at which a new element comes in: muscular action. With the onset of muscular action, which is mainly involuntary, even when it affects the voluntary muscles, detumescence proper begins to take place. Henceforward purposeful psychic action, except by an effort, is virtually abolished. The individual, as a separate person, tends to disappear. He has become one with another person, as nearly one as the conditions of existence ever permit; he and she are now merely an instrument in the hands of a higher power--by whatever name we may choose to call that Power--which is using them for an end not themselves. The decisive moment in the production of the instinctive and involuntary orgasm occurs when, under the influence of the stimulus applied to the penis by friction with the vagina, the tension of the seminal fluid poured into the urethra arouses the ejaculatory center in the spinal cord and the bulbo-cavernosus muscle surrounding the urethra responsively contracts in rhythmic spasms. Then it is that ejaculation occurs.[106] "The circulation quickens, the arteries beat strongly," wrote Roubaud in a description of the physical state during coitus which may almost be termed classic; "the venous blood, arrested by muscular contraction, increases the general heat, and this stagnation, more pronounced in the brain by the contraction of the muscles of the neck and the throwing of the head backward, causes a momentary cerebral congestion, during which intelligence is lost and the faculties abolished. The eyes, violently injected, become haggard, and the look uncertain, or, in the majority of cases, the eyes are closed spasmodically to avoid the contact of the light. The respiration is hurried, sometimes interrupted, and may be suspended by the spasmodic contraction of the larynx, and the air, for a time compressed, is at last emitted in broken and meaningless words. The congested nervous centers only communicate confused sensations and volitions; mobility and sensation show extreme disorder; the limbs are seized by convulsions and sometimes by cramps, or are thrown wildly about or become stiff like iron bars. The jaws, tightly pressed, grind the teeth, and in some persons the delirium is carried so far that they bite to bleeding the shoulders their companions have imprudently abandoned to them. This frantic state of epilepsy lasts but a short time, but it suffices to exhaust the forces of the organism, especially in man. It is, I believe, Galen, who said: 'Omne animal post coitum triste præter mulierem gallumque.'"[107] Most of the elements that make up this typical picture of the state of coitus are not absolutely essential to that state,