As Amenorrhœa, or retention of the menses, is generally the effect of a morbid state of the body, it follows that remedies capable of acting as Emmenagogues can only be _relative_ agents, unless indeed we are disposed to accede to the opinion so generally maintained in the writings of the older physicians, but now generally discarded, _that certain substances exert a specific[156] action upon the uterus_. It may certainly be asserted without fear of contradiction, that there are many substances which, when received into the stomach, have their stimulant operation more particularly determined to one part than to another; alkalics, for example, to the kidneys; cantharides to the bladder; mercury to the salivary glands, &c. Reasoning therefore by analogy, it was not unphilosophical to conclude, that similar medicines might exist with respect to the uterus; but experience has negatived the supposition, there being no proof of any of the substances styled _Emmenagogues_ producing their effects by any _specific_ influence upon the uterine system. If the term _Emmenagogue_ be assumed conventionally, according to this view of the subject, it may be retained without any fear of error, otherwise it would be wiser to remove the name from our classification. The suppression of the catamenia usually depends upon a debilitated state of the body, although it is sometimes the consequence of a plethoric diathesis; in the former cases tonics, in the latter, venesection may display the powers of an emmenagogue; upon which occasion, I have frequently derived the greatest benefit by cupping the patient upon the loins. Where the disease occurs in young women, about the age of puberty, it is very generally connected with extreme debility of the system; the preparations of iron, bark, and other invigorating medicines, are accordingly the most likely to succeed in its cure. Whereas in full florid habits, when the catamenia are suddenly suppressed, _Laxatives_, _Diaphoretics_, or _blood-letting_, afford the surest means of relief. There are two other classes of medicine which may occasionally prove emmenagogue—ACRID PURGATIVES, which act upon the rectum, and hence by _contiguous sympathy_ upon the uterus, as _Aloes_, &c. and STIMULATING DIURETICS, as _Cantharides_, the _Turpentines_, &c. which are supposed to excite the womb, sympathetically, by their stimulus upon the bladder. Nor is the advantageous influence of mercury to be overlooked, which, in cases of morbid action in the secreting functions, prove a Herculean remedy. DIURETICS: Medicines which increase the urinary discharge. This effect is produced by very different modes of operation; and as some of them are mutually incompatible with each other, it is essential that we should understand the _modus operandi_ of each individual of which the class consists, in order that we may direct its application with precision.