That this erection-center is in some degree under brain control, is shown by the fact that sudden shock of any kindóbeing surprised in the sexual act, fear of an unsuccessful attempt at intercourse, or other causes having their origin solely in the brainódestroys the erection; and also by the fact that the sexual act may be considerably prolonged by keeping the mind fixed upon an entirely different subject.

1 The pedunculi cerebri and the pons are probably nervous paths through which sexual impressions are conveyed to the brain, the erection-center being stimulated by direct irritation of the nerve-tracts of the corpora, as well as by peripheral irritation of sensory nerves of the penis, clitoris and their annexa. The nervi eriirentes, running in the first three sacral nerves, convey to the muscles of the penis the erectile impulse, in this case an inhibitory one, acting, according to Kolliker and Kohlrausch, upon the ganglionic nerve mechanism of the corpora cavernosa, relaxing the latter's smooth muscular fibers and permitting the free entrance of blood into their spaces. By simultaneous contraction of the bulbo cavernosus, and ischjo cavernosus muscles, which have an aponeurotic insertion in the dorsal surface of the penis, the return of the blood is impeded and erection produced. For further information on this somewhat involved subject, see Goltz, Eckhard, Ferner, "Functions of the Brain;" and Zuckerkand], "Ueber das Reichcentrum."

Thus 1 was once told by a lady, who evidently thought she could not become pregnant without, as she said, "feeling good," that she kept from having children by "thinking about baking flannel-cakes all the time John was doing it." Of course her theory was wrong, and we can only regret the good things she missed by too strict a devotion to duty; but she is not the first nor the last to suffer from ignorance.