In the 1st of 3 experiments performed to investigate the relation between the intensity of sexual stimulation and the temporal regulation of that stimulation by estrous female rats, deposit of the vaginal plug was experimentally controlled. Females showed shorter response intervals after ejaculations when plug deposit was prevented than when it was not. In Experiment 2 females' vaginas and perineal regions were treated with an anesthetic. Response intervals following all 3 types of sexual contact were less during anesthetic sessions than during control sessions. In Experiment 3 females were serviced by males who could not effect intromission. Under these conditions females exhibited relatively short contact-response intervals throughout 1-hr, testing sessions.

SUMMARY Male rats injected with 10 mg. cyproterone acetate daily for 28 days were given weekly mating tests with receptive females. At the conclusion of testing the animals were killed and the testes and seminal vesicles were weighed. These organs and the glans penis were then prepared for microscopic analysis. The experimental treatment had no detectable effect upon copulatory behaviour nor upon the testis or the cornified papillae in the integument of the glans penis. The seminal vesicles of treated males appeared to be non-secretory and were lighter than those of control rats but heavier than the vesicles of untreated castrates. It is concluded that although cyproterone acetate partially blocked the action of endogenous androgen on the seminal vesicles it had neither a blocking effect on the penile papillae nor on the central nervous mechanisms which mediate mating responses.

Observations and experiments relating to the causes and results of ejaculation in male mammals of several species reveal that in a number of different mammals, erection and emission can be mediated by purely spinal mechanisms. In intact males, emission is possible without genital stimulation, and the occurrence of emission is not automatically associated with orgasm in men or with the normal behavior sequelae to ejaculation produced in animals by copulation. These and other similarities between sexual reflexes in primates, carnivores, and rodents are taken to indicate the potential values of a broadly comparative approach to human sexual functions.A FUNDAMENTAL REACTION included in the copulatory behavior of all male mammals is the ejaculatory response which results in delivery of sperm into the female reproductive tract and therefore constitutes an essential link in the behavior chain leading to reproduction and perpetuation of the species. An indispensable element in the total pattern is, of course, the expulsion of seminal fluid comprising secretions from the prostate and seminal vesicles as well as sperm. However, seminal emission normally occurs in conjunction with several other reactions which are equally necessary for insemination of the female. These ancillary responses include penile erec-

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