It is not rare to see women, in whom, after this third stage, a new dis charge of almost pure blood follows; only this discharge ordinarily lasts but twenty-four hours, and is followed by a purely mucous discharge, which may last thirty-six or forty-eight hours.
Some writers have claimed that menstrual blood differs from ordinary blood in its viscosity and lack of coagulability, and wish to make a diag nostic sign of it from the blood that accompanies an abortion. This is absolutely a wrong statement, for there are a large number of women who discharge clots at the time of their menses; and we would fall into serious error if we should consider the presence of clots in the hemorrhage com ing from the genital organs as an indication of a miscarriage. The men strual blood was thought for a long time to be a poisonous fluid, having an injurious effect on living things, men, animals, and plants. This is erroneous, of course. Chemical analysis has shown that the menstrual blood does not differ greatly from ordinary blood. But, although the menstrual blood is not poisonous, it is not the less true that the mucous element which it contains has at times irritating and injurious qualities, which cause a peculiar form of chronic inflammation of the urethra, which has been well studied by Diday (of Lyons). If these accidents can hap pen in our temperate climate, they can, with more reason, occur in hot climates; hence the wisdom of the law of Moses which forbade cohabi tation with woman during the menstrual period.
Progress and Duration of the Menses.
The chief characteristic of the menses is their periodicity, but, although they are periodic, the interval between the periods is not the same in all cases; it can even vary in the same woman. In most cases, this interval is from twenty-five to thirty days, but there are some women in whom the menses are ahead of or behind an exact number of days. According to Paul Dubois and Courty, the interval should be a solar month of thirty days and not a lunar month of twenty-eight days; but it is useless to try to fix an exact date, for irregularities in return are very frequent. They are the rule at the commencement of puberty, and at the menopause, and the menses very frequently change from the effects of marriage and repeated pregnancy. In some women, in the interval between the two periods, toward the middle of the intermenstrual time, there occur, unexpectedly, signs of uterine and ovarian hyperemia, accompanied, or not, by a slight bloody discharge, called the supernumerary menses.
Although the menses vary greatly in periodicity, there are still greater variations when we wish to determine the duration of the menstrual dis charge. Ordinarily it is from three to six days, but exceptions are fre quent.
The following is a table (from Paul Dubois) showing the duration of the menstrual period in 600 women: According to this table the largest number of women menstruate for eight days, but Paul Dubois says, with truth, that by eight days the women really mean seven, or one week.
Physiological Characteristics of the Menses.
This is a question which it is yet actually impossible to answer. The menstrual flow was considered by the ancients as a means of unloading the organism, from month to month, of the surplus of blood; this explan ation, which is based on the old theory of plethora, is not admissible to day, for it has been proved that, during pregnancy, not only is there no plethora but that there is anEemia. But, if the menstrual flow is not intended to unload the organism of surplus blood, it has another object according to Andral and Gavarret. These writers say, that the quantity of carbonic acid exhaled by the lungs increases in women until puberty, from this time on it diminishes, increasing again after the menopause. The suspension of the menses, which is determined by pregnancy, nurs ing, amenorrhoea, etc., restores the increase of carbonic acid as after the menopause. The purpose of the menstrual flow would then be to increase in women the phenomena of combustion; it would therefore be a kind of natural emunctory.
Although the menses are periodical and regular, there are certain causes which, for the time being, suspend them during the active period of the genital system. Some of these causes are physiological, as pregnancy and confinement; others are of a pathological nature.
Pregnancy almost always stops the menses, and cases of women men struating during pregnancy should be absolutely rejected, unless they are admitted as entirely exceptional. The menses commence again about six or seven weeks after confinement, but this is not certain, for they are not rarely delayed until the end of the second and even of the third month.
It is lactation which stops the menses, at least during the first months. The return of the menses in the wet-nurse is generally indicated by the bad quality of the milk. But, in the wet-nurse, the stopping of the men ses does not interfere with ovulation, and this is proved by the remark able number of women who become pregnant while nursing. Besides these physiological causes, there are others which induce the cessation of the menses from a pathological stand-point; such as, quick and violent emotions, cold, hemorrhage and, finally, the essential fevers. These last, it is true, are not always active in causing the cessation of menstruation, but they have a remarkable influence on it; thus, in some cases they in crease the bloody discharge; in others, and more frequently, diminish or even entirely stop it.