Before ejaculation begins, the urethral glands already begin to secrete; and when erection is powerful and prolonged, this secretion often makes its appearance at the urethral orifice in the form of drops of a clear somewhat tenacious fluid. _Ultzmann_ considers that the function of this secretion is probably to moisten the walls of the urethra, over which the acid urinary secretion is continually flowing, with a protective alkaline fluid, and thus to prepare the canal for the passage of the semen. An analogy may be found in the secretion of the cervical glands of the uterus in the female, for this secretion has been found to enhance the activity of the movements of the spermatozoa. If now during copulation the moment of ejaculation begins, the male experiences at the same time a sense of voluptuous pleasure and a feeling of muscular spasm in the perineal region, and this indicates the commencing evacuation of the contents of the seminal vesicles through the ejaculatory ducts. Simultaneously, the secretion of the prostate is poured into the urethra. The semen now gradually passes out through the narrow ejaculatory ducts, and, since in consequence of the swelling of the caput gallinaginis, it cannot pass backwards towards the bladder, it runs forwards, and accumulates in the bulb of the urethra, the physiological excavation of that tube. As soon as a considerable quantity of the semen has collected in this situation, so that the bulb of the urethra becomes distended, reflex contractions of the bulbocavernosus muscles ensue, by means of which the seminal fluid is forced out of the urethral orifice. In cases in which this muscular apparatus does not function properly, as in the paralytic form of impotence, the semen during ejaculation is not ejected in a forcible jet, but rather flows slowly, as from a lax tube partially filled with fluid, from the urethral orifice.