It is no longer possible to accept the view of earlier physiologists that the purpose of this erection of the lower segment of the uterus is “to constitute with the penis a continuous canal between the male and the female genital organs.” Contact between the glans penis and the os uteri externum is not indeed an occurrence of extreme rarity; but, on the other hand, it is in no sense a constant nor even a frequent incident of sexual intercourse. It is ejaculation, especially, which is subserved by the erection of the vaginal portion of the cervix. In the female, ejaculation occurs at the moment of the most intense sexual pleasure, and is marked by the evacuation from the os uteri externum of a moderate quantity of mucous fluid with an alkaline reaction. In some cases, in which a chronic discharge of this cervical mucus occurs, it forms an elongated coagulum of delicate vitreous jelly, the “mucus-string” of _Kristeller_. The last-mentioned author is of opinion that the spermatozoa slowly, but by active movements, find their way along this string into the cavity of the uterus. This assumption, however, is met by _C. Mayer_ and _Marion Sims_ with the objection, that _Kristeller’s_ observations were for the most part carried out on women who were out of health, and that a gelatinous secretion of this character obstructs the orifice of the cervical canal, and hinders the occurrence of conception. From the erection of the portio vaginalis during sexual excitement, and its sudden relaxation post cohabitationem, _Wernich_ deduces the occurrence of a process of aspiration, by which the semen is drawn up through the cervical canal into the cavity of the uterus; a process which has been seen in actual occurrence in vivisected animals. It is said that to many women this feeling of a process of suction is so well known, that thereon, in association with the consequent almost complete absence of mucus and seminal fluid from the vagina, they are accustomed to base a belief that conception will occur. It is said that this aspiratory activity on the part of the uterus may be perceived during coitus by the male also (?). It is assumed by _Grohe_ that the wave motion of the cilia of the epithelium lining the cervical canal, is of importance in promoting the ascent of the spermatozoa; it may be that the vibration of the cilia exercises a motile stimulus on the spermatozoa, it may be that the continually repeated stroke of the cilia serves to prevent the permanent agglutination of the spermatozoa into groups. According to _Sims_, the aspiratory action of the uterus is effected in the following manner: By the contraction of the constrictor vaginae superior muscle, the cervix is pressed downwards against the glans penis, and by this pressure its contents are evacuated; the parts then relax, the uterus suddenly returns to its normal state, and thus the seminal fluid with which the vagina is filled is drawn into the interior of the cervical canal.