188 PHYSIOLOGY CHAP. 



penetrate, it presents notable differences according to the age 

 and the previous activity of the organ, and in healthy women 

 there is often to be seen projecting from it a plug of mucus 

 secreted by the cervical canal, clear, viscous, and alkaline in 

 reaction (Fig. 71). 



Even in apathetic women who do not take any active part in 

 coitus, as also in women who are unconscious, or have fainted 

 during forced criminal connection, it is an undoubted fact that the 

 sperm ejaculated into the vagina can enter through the cervical 

 canal ; on this account it must be admitted that this penetration 

 can happen independently of any activity of the uterus or vagina. 

 This being the case, what is the mechanism of penetration ? The 

 experiments of Seligmann (1896) make it very probable that this 

 happens by a negative chemotaxis of the spermatozoa to the 

 acidity of the vaginal mucosa, and by a positive chemotaxis to 

 the alkaline mucous plug which normally projects from the 

 external orifice of the uterus ; in this way they pass quickly from 



FIG. 71. External orifice of uterus. (Waldeyer.) 1, of child ; 2, 3, of nullipara ; 4, of multipara ; 



cm, mucous plug. 



acid surroundings into alkaline, in which they can travel through 

 the cervical canal, and penetrate into the body of the uterus. 



But in women who take a more or less active part in sexual 

 intercourse, and they are I believe the great majority, it must 

 be held that all the genital apparatus provided with contractile 

 elements, by participating in the sexual act, favours in various 

 ways the penetration of the sperm into the uterus. From their 

 observations, many gynaecologists conclude that during coitus 

 the vagina, with its rich muscular supply, as well as the uterus, 

 with its muscular walls and muscular round ligaments, contract, 

 and enter into a condition of more or less intense excitation. In 

 this connection the mode of action of the mouth of the uterus is 

 of interest ; this the English gynaecologist, J. Beck, observed 

 directly in a woman affected by prolapse of the uterus and in 

 whom the os uteri showed itself through the vulva. It was 

 sufficient to excite the projecting neck with the tip of the finger 

 to produce within a short time the venereal orgasm. " The 

 uterine neck (wrote Beck) at the beginning was hard, immobile, 

 and had the normal aspect: its aperture was closed and did not 

 admit the passage of a sound. Almost immediately after contact 

 with the finger the mouth opened widely, gaped 5 or 6 times, 



