If a liquid medicine be preferred, I order a dram of these dried leaves to be infused for four hours in half a pint of boiling water, adding to the strained liquor an ounce of any spirituous water. One ounce of this infusion given twice a day, is a medium dose for an adult patient. If the patient be stronger than usual, or the symptoms very urgent, this dose may be given once in eight hours; and on the contrary in many instances half an ounce at a time will be quite sufficient. About thirty grains of the powder or eight ounces of the infusion, may generally be taken before the nausea commences.
The ingenuity of man has ever been fond of exerting itself to vary the forms and combinations of medicines. Hence we have spirituous, vinous, and acetous tinctures; extracts hard and soft, syrups with sugar or honey, &c. but the more we multiply the forms of any medicine, the longer we shall be in ascertaining its real dose. I have no lasting objection however to any of these formulæ except the extract, which, from the nature of its preparation must ever be uncertain in its effects; and a medicine whose fullest dose in substance does not exceed three grains, cannot be supposed to stand in need of condensation.
It appears from several of the cases, that when the Digitalis is disposed to purge, opium may be joined with it advantageously; and when the bowels are too tardy, jalap may be given at the same time, without interfering with its diuretic effects; but I have not found benefit from any other adjunct.
From this view of the doses in which the Digitalis really ought to be exhibited, and from the evidence of many of the cases, in which it appears to have been given in quantities six, eight, ten or even twelve times more than necessary, we must admit as an inference either that this medicine is perfectly safe when given as I advise, or that the medicines in daily use are highly dangerous.
EFFECTS, RULES, and CAUTIONS.
The Foxglove when given in very large and quickly-repeated doses, occasions sickness, vomiting, purging, giddiness, confused vision, objects appearing green or yellow; increased secretion of urine, with frequent motions to part with it, and sometimes inability to retain it; slow pulse, even as slow as 35 in a minute, cold sweats, convulsions, syncope, death.[11]
When given in a less violent manner, it produces most of these effects in a lower degree; and it is curious to observe, that the sickness, with a certain dose of the medicine, does not take place for many hours after its exhibition has been discontinued; that the flow of urine will often precede, sometimes accompany, frequently follow the sickness at the distance of some days, and not unfrequently be checked by it. The sickness thus excited, is extremely different from that occasioned by any other medicine; it is peculiarly distressing to the patient; it ceases, it recurs again as violent as before; and thus it will continue to recur for three or four days, at distant and more distant intervals.
These sufferings of the patient are generally rewarded by a return of appetite, much greater than what existed before the taking of the medicine.