The treatment adapted to poisoning from a large dose of digitalis, if the patient has not vomited, is to administer ipecacuanha till this effect is produced; if vomiting has taken place, to assist in washing out the stomach by means of copious draughts of warm water or demulcent drinks, to which tannic acid may be added, in order to form an insoluble compound with the active principle. Afterwards, opium should be administered by the rectum or stomach, a sinapism applied to the epigastrium, and the strength supported, if necessary, by wine-whey, carbonate of ammonia, etc.

Probable influence of the alcohol in certain sedative tinctures. One method of accounting for the comparative inefficiency of certain sedative tinctures, is the supposition that, in large doses, the stimulating property of alcohol may be sufficient, in greater or less degree, to counteract the depressing agency of the sedative medicine contained in them. if it is true that the tincture of digitalis, in those instances in which it has been given so largely with little or no effect, has been prepared from efficient leaves, I know no other way to account so satisfactorily for its apparent failure. We habitually resort to alcoholic stimulants to obviate the prostration from certain nervous and cerebral sedatives in excess, as tobacco, aconite, conium, hydrocyanic acid, etc. Why, then, should not these same stimulants produce the same effect, when given in connection with the sedative, provided the periods for their action and that of the sedative coincide ? I have little doubt that the amount of extract which a fluidounce of tincture of digitalis would yield, upon evaporation, would prove very serious if not fatal, in the cases in which the tincture is said to have been taken with impunity. (Note to the third edition.)

Permanence of Operation and Cumulative Tendency. There are two circumstances in the operation of digitalis, which, from their practical importance, require particular notice. One of these is the long continuance of its effects, after having been once produced, without its further administration, and the other its tendency to a cumulative operation.

Not unfrequently the reduction of the pulse produced by digitalis, or the increased flow of urine occasioned by it, will last to a greater or less extent for days, if brought about by the continued use of small doses of the medicine; and, when any decided symptoms appear, they do not subside completely until after seven or eight days or more.

Soon after foxglove came into use, attention was called to its remarkable property, after having been given daily, in small but increasing doses, for a considerable time, without observable effect, of beginning abruptly to act with great energy, as if with the accumulated effect of all that had been previously taken. Alarming instances of this kind were not unfrequently observed; and sometimes fatal effects occurred. Dr. Blackall mentions a case, in which death appeared to be caused by two drachms of the infusion, taken daily for some time. I myself, many years since, witnessed the death of a boy, with symptoms strongly resembling those of poisoning by digitalis, who had for some time been taking the ordinary doses, without effect, for dropsy. Nevertheless, I have no doubt that the danger from this cause has been over-estimated; and many have been deterred from the efficient use of the medicine by causeless apprehension. It is always proper to commence with a small dose, smaller indeed than will be likely to produce any visible effect of itself; because there is in some a most remarkable susceptibility to the action of the medicine. Even two grains have produced alarming symptoms. But with this caution, and due care and watchfulness in the increase of the dose, I believe that the therapeutic influence of the medicine can always be obtained without danger. In regard to its cumulative operation, should no observable effect have been produced, with gradually increasing doses, by the time that a poisonous quantity has been taken altogether, a drachm of the powder, or a fluidounce of the tincture for example, it would be advisable to suspend the medicine for a few days, and afterwards resume, if thought advisable.

Slow Diminution of Susceptibility. Another fact of value, in refervol. II. - 8 ence to the operation of digitalis, is that the susceptibility to its influence decreases slowly; so that, after having ascertained the effective dose, it will not be necessary, as in the case of opium and other cerebral stimulants, to increase it rapidly in order to sustain a given effect.

2. Mode Of Operation

After what has been already said, little will be required upon this point. The reader is aware of my belief that digitalis is a local excitant, and that, when given in large doses by the stomach, it is capable of irritating or even inflaming that organ, and thus of producing a general sympathetic excitement, attended with increased frequency of pulse and heat of the body; but that, when taken in quantities insufficient to irritate the stomach, it is in no degree capable of exciting the heart, or augmenting the temperature. He is also aware, that I consider the essential effects of the medicine upon the system generally, to be sedative to the nervous centres and the circulation, and to the latter through its influence on the former. There can be no doubt that these effects are produced through absorption. it is true that the active principle of digitalis has not been detected with certainty in the urine; but the proportion of digitalin is so exceedingly minute, in relation to the effect produced, that this should not be expected. The proof of absorption is afforded by the facts, that, when injected into the cellular tissue, it is capable of producing the same effects as when exhibited by the stomach; that its diuretic operation has been induced by its application to the surface of the body; and that, when introduced into the blood-vessels, it acts in the same manner as when brought in other modes into contact with the body, though more rapidly. The evidence of its primary influence upon the nervous centres, and through them on the heart, is afforded by the fact already stated that, if the par vagum be divided on both sides, it ceases to reduce the heart's action, and in moderate quantities produces no effect upon it. The dark and liquid state of the blood, and the loss of contractility of the heart, are probably due also to an influence exercised upon these two vital constituents of the system through the encephalic centres.