The vaginal secretion under certain pathologic conditions may become so acid that it induces sterility. Women who suffer m severe vaginal catarrh are frequently sterile, the spermatozoa being found dead in the vagina some hours after copulation, although an examination a shorter time afterward revealed them still alive. In cases where conception takes place in spite of a very acid condition of the vaginal secretion, it is probable that some of the spermatozoa enter the uterus before the secretion has had time to act on them, or possibly the spermatozoa being injected in a mass, the acid secretion is unable to penetrate and kill them all.
The reaction of the normal vaginal mucus is always acid, that of the cervix alkaline; but as the result of the inflammatory condition, the reaction of each is often intensified, especially that of the vagina, which has an exceedingly sour and penetrating odor. This acid discharge, bathing the neck of the uterus, penetrates more or less into the cervical plug and causes coagulation of the alkaline mucus.
The chief constituent of the semen is albumin; agents which affect albuminous substances influence the functional activity of the spermatozoa heat, concentrated acids, and probably concentrated alkalies. In normal conditions the alkalinity of the seminal fiuid seems to be sufficient to neutralize the acidity of the vaginal secretions, so that the spermatozoa may remain seventeen days or more (Bossi) within the vaginal canal, even during a menstrual period, without having their vitality destroyed.
When hyperacidity of the vaginal secretion is present, it is probable that the fertilizing element is at once rendered inert; but should some of the spermatozoa succeed in reaching the interior of the cervical canal, the increased alkalinity of the secretion there would in all probability put an end to all further progress.
The conditions, then, which appear to prevent fecundation are: First, the absence of the proper nidus for the ovum; second, the obstruction of the cervical canal by a mucus plug; third, increased alkalinity of the cervical secretion, often accompanied by the increased acidity of the vaginal secretion. Three conditions must, then, be determined: First, are there spermatozoa in the semen? Second, do they get into the uterocervical canal? Third, do the secretions in the canal poison the spermatozoa?
"For those who are very anxious for offspring," wrote Marion Sims, "I usually order sexual intercourse on the third, fifth, and seventh days after the flow has ceased; and on the fifth and third days before its return. For the most obvious reasons this would always be before going to bed at night, instead of just before rising in the morning. The horizontal position favors the retention of semen; the erect its expulsion. I am satisfied that too frequent sexual indulgence is fraught with mischief to both parties. It weakens the semen; in other words, that this is not so rich in spermatozoa after too frequent indulgence; and when carried to the extent of a debauch, the fiuid ejaculated may be wholly destitute of spermatozoa. Thus it will be seen that it will be much better to husband the resources of both man and wife."
The Prevention of Conception and the Limitation of Offspring. Some of the contraindications to procreation are when either parent suffers from a disease which is transmissible, and such diseases frequently manifest themselves only after marriage; when the pregnancy would endanger the mother's life, or even where the pregnancy is a nine months' torture to her; where either parent is suffering from ill health; or where for economical reasons no more children are desired.
If there exists no condition in either parent or in their circumstances why they should not have children, the next consideration due to their children, is how the same may be procreated under the most favorable conditions possible; this condition can only be secured by making the circumtsances such that the mother shall be able to choose the time for their conception when both parents are in the best physical condition. That children should be brought into the world haphazard, as the result of accident, is to degrade the human race below that of the lower animals, where the female admits the male only at the time of the rut, which in the majority of cases occurs only once a year.
Another requisite to bearing healthy children is that the pregnancies shall not follow each other too rapidly. Aside from the consideration for the health of the mother herself, she must be in good physical condition to bear the healthiest children she is capable of giving birth to; and for this there must be from two and a half to three years between the successive pregnancies. The results of overproduction on the children are frequently, that they are sickly, short-lived, or suffer from rickets, cerebral paralysis, idiocy, or imbecility.
And last, but certainly not least, many women become chronic invalids, or are hastened to premature graves, by having children as fast as they possibly can.