HAVING glanced briefly at betrothal, marriage, and divorce, their relation to society, and the law of attraction between the sexes, I come now to consider, prior to an attempt to deal with the sexual impulse itself, that crowning pleasure of life—sexual intercourse* and the task is by no means easy. The taste of an orange, though pleasant, and simple, is exceedingly difficult to describe; and at the very threshold of the subject we are met by physiological facts and phenomena which must be dealt with in the plainest possible manner, if we would have what we set out to say rendered clear and unambiguous. The system hitherto adopted, by writers on sex themes, of clothing a portion of their subject in a foreign language,—French, German, or Latin,—I am not in sympathy with. It not only fails in many cases of the very purpose aimed at in the work, of imparting useful information, but adds the silliness of a mock-modesty, and thinly veiled secrecy, to what is an eminently proper subject for scientific discussion. For these reasons I have concluded to adopt a perfectly frank tone, in the mquiry yet before me, as not only best adapted to the full and unhampered expression of my views, but as, to my mind, by far the less immodest method. Therefore, "if any man be offended, let him turn the buckle of his girdle; I care not I"

The modus operandi of the sexual act itself is so well understood as to require little explanation. My experience is that boys and girls, even, who do not understand it are usually of exceedingly tender years. During sexual maturity desire is a physiological law. Girls living in cities come under its influence a year earlier, as a rule, than those living in the country; and the larger the city, the earlier development takes place.1

In women the activity of the reproductive organs is briefer than with men, in whom the sexual power, as I have already shown, sometimes continues into advanced age. There are no well-authenticated cases of very late fecundity in women; and "the deadnees of Sarah's womb," spoken of by Paul,2 was only overcome—if at all—by miraculous agency.

The sexual instinct is, primarily, a function of the brain; and while as yet there is some doubt as to its localized region therein, the fact that thought, either as a result of sight, or touch, or without either, is commonly necessary to procure erection of the penis in the male, and tumescence in the female, sufficiently indicates that those conditions are of cerebral origin. Goltz and Eckhard placed the erection-center between the brain and sexual apparatus, connected with both by the sensory nerves.' This center may be excited by psychical or intrinsic irritation of the nerve-tract in the brain, or cervical portion of the spinal cord, as well as by external irritation of the sensory nerves of the penis of the male, the clitoris of the female, or other parts of the body which are known to exercise an influence upon the power of erection,—in the latter instances the erection taking place independently of will power.

Simultaneously with such irritation, there is a dilatation of the capillary blood-vessels of the penis or of the clitoris, with their surrounding vascular structures, and pressure being exerted upon the former by distention of the involved organs, the return of the blood is impeded; this retention of the blood is aided by the contraction of the muscles of the part, and erection supervenes, brief or prolonged, weak or vigorous, in proportion to the control which the nerve and muscular systems exercise upon the vascular and erectile tissues.

Reflex irritation of the center may be caused by disease of the urethra (gonorrhea); by disease of the rectum (haemorrhoids); of the bladder (cystitis); and by normal distention of the seminal vesicles. The erections occurring during sleep are most commonly due to the latter cause, although sometimes produced by pressure of the intestines upon the pelvic bloodvessels, from lying on the back.