024. Digitalis purpurea. Common Fox-glove.
Synonyma. Digitalis. Pharm. Lond. & Edin.
Digitalis foliis calycinis ovatis, galea simplice. Hal. Stirp. Helv. no. 330.
Virga regia major, flore purpureo. Caesalp. 348.
Aralda Bononiensibus. Gesner.
Digitalis purpurea vulgaris. Park. 1653.
Digitalis Purpurea. Gerard. Herb. 790. J. Bauh. II. 811. Raii Hist. 767. Synop. p. 283. Flor. Dan. 774. Curtis Flor. Lond. Withering's Account of the Fox-glove.
α Digitalis purpurea, folio aspero. Bauh. Pin. 243.
β Digitalis alba, folio aspero. Bauh. Pin. 244. Hort. Kew.
Class Didynamia. Ord. Angiospermia. L. Gen. Plant. 758.
Ess. Gen. Ch. Cal. 5-partitus. Cor. campanulata, 5-fida ventricosa. Caps. ovata, 2-locularis.
Spec. Char. D. calycinis foliolis ovatis acutis, corollis obtusis: superiore integro.
The root is biennial, branched, and fibrous; the stalk is erect, simple, tapering, covered with fine hairs or down, and rises commonly to the height of four or five feet; the leaves are large, oval, narrowed towards their points, obtusely serrated, veined, [On the under side these veins form a kind of net-work.] downy, and stand upon short winged footstalks; the floral leaves or bracteas spear-shaped, sessile, purplish towards the point; the calyx consists of five segments, which are elliptical, pointed, nerved, or ribbed, and the uppermost segment is narrower than the others; the flowers grow in a long terminal spike, chiefly on one side, they are large, monopetalous, pendulous, bell-shaped [The flowers bear some resemblance to the finger of a glove; hence the name Digitalis.] purple, and marked on the inside with little eyes, or dark coloured dots, placed in whitish rings; the tubular part appears inflated, and almost cylindrical, but swelling towards the base, and opening at the limb into four irregular, short, obtuse segments, of these the uppermost is the shortest, appearing truncated or cut off transversely; the peduncles are round, short, villous, and bend downwards by the weight of the flowers; the filaments are two long and two short, white, crooked, inserted in the bottom of the tube, and crowned with large oval yellow antherae; the style is simple, and thickening towards the stigma, which is bifid; the germen is oval, and surrounded at the bottom by a small nectarious gland; the capsule is bilocular, and contains many blackish seeds. It grows commonly about road sides and hedges, especially in dry gravelly soils, and flowers in June and July.
The leaves of Fox-glove have a bitter nauseous taste, but no remarkable smell; they have been long used externally to sores and scrophulous tumours with considerable advantage. Respecting the internal use of this plant we are told of its good effects in epilepsy, scrophula, and phthisis; but the incautious manner in which it was employed rendered it a dangerous remedy: thus we find Ray (after reciting the case of epilepsy cured by it, as mentioned by Parkinson,) says, "Verum medicamentum hoc robuflioribus tantum convenit, siquidem violenter admodum purgat & vomitiones immanes excitat:" [Raii Hist. p. 767.] and others, speaking of its successful exhibition in scrophula, remark, "Sed ob nimiam remedii vehementiam, continuationem ejus necessariam detrectavit." [Vide Murray's Ap. Med. vol. 1. p. 192.] Yet while Digitalis was generally known to possess such medicinal activity, its diuretic effects, for which it is now deservedly received in the Materia Medica, were wholly overlooked; that to this discovery Dr. Withering has an undoubted claim, and the numerous cases of dropsy, related by him and other practitioners of established reputation, afford incontestible evidence of its diuretic powers, and of its practical importance in the cure of those diseases. [See his account of the Fox-glove, published 1785; a book, which, in the opinion of Dr. Cullen, "should be in the hands of every practitioner of physick," (M. M.)] From Dr. Withering's extensive experience of the use of the Digitalis in dropsies, he has been enabled to judge of its success by the following circumstances:—"It seldom succeeds in men of great natural strength, of tense fibre, of warm skin, of florid complexion, or in those with a tight and cordy pulse. If the belly in ascites be tense, hard, and circumscribed, or the limbs in anasarca solid and resisting, we have but little hope. On the contrary, if the pulse be feeble, or intermitting, the countenance pale, the lips livid, the skin cold, the swollen belly soft and fluctuating, the anasarcous limbs readily pitting under the pressure of the finger, we may expect the diuretic effects to follow in a kindly manner." [l. c. p. 189. & seq.] Of the inferences which he deduces, the fourth is, "that if it (Digitalis) fails, there is but little chance of any other medicine succeeding." Thus we are to infer, that men of great natural strength, and under the other circumstances just mentioned, when affected with dropsy, have little to hope for from the use of this diuretic, and still less from any other medicine. [In such cases Dr. W. attempts to induce a change in the constitution, and thereby to fit it for the action of the Digitalis. Would not repeated purging, according to Sydenham's plan, succeed best in these cases?] As this observation is the result of experience, and of considerable practical consequence, we wish particularly to press it on the attention of the medical reader. Although the Digitalis is now generally admitted to be a very powerful diuretic, and many cases may be adduced of its successful use [The author could bring many instances were it necessary, of the good effects of the Digitalis: a clinical patient at Guy's Hospital, treated by Dr. Relph last winter, afforded a striking proof of the efficacy of this medicine in hydrothorax.] in addition to those already published, yet it is but justice to acknowledge that this medicine has more frequently failed than could have been reasonably expected, from a comparison of the facts stated by Dr. W. [Among the principal of the unsuccessful cases we may notice the eight fatal ones related in the Medical Memoirs by Dr. Lettsom. In reply to these cases, Dr. Withering sent me the following Letter, which is published by the permiflion of Dr. Lettsom, who authorizes me to say, that as his only object in this business is the investigation of truth, he willingly appeals to the justice and candour of the public, how far his practice is fairly represented in Dr. Withering's letter: SIR, Please to accept my thanks for your offer of inserting any thing new which I might have to say reflecting the Digitalis; but I really have nothing new to observe, nor have I any thing to retract of what I have said before. Under my own management, under that of the medical practitioners in this part of England, and I may add, also in the hands of some worthy and respectable Clergymen in village situations, it continues to be the moil certain, and the least offensive diuretic we know; in such cases, and in such constitutions, as I have advised its exhibition. I have also the satisfaction to find, by letters from some of the most eminent Physicians in different parts of England, that it is equally useful and safe in their hands. But I complain of the treatment this medicine has had in London. Its ill success there cannot be altogether owing to difference of constitutions. Dr. Lettsom has related his unsuccessful attempts with a degree of courage, and of candour, which do the highest honour to his integrity; (Memoirs of the Med. Society of London, vol. II., p. 145.) but no one can compare his choice of patients, with my declarations of the fit and the unfit, or the doses he prescribed, and the perseverance he enjoined, with my doses, rules, and cautions, (Account of the Fox-glove p, 181, 184, et seq.), without being astonished that he could suppose he had been giving this medicine "in the manner prescribed by me." (Memoirs of the Medical Society of London, vol. II. page 169.)—I am fully satisfied, that, had I prescribed it in such cases, such forms, such doses, and such repetitions as he has done, the effects would, in my hands, have been equally useless, and equally deleterious. I must therefore suppose, that he had forgotten what I had written, without being conscious that his memory had deceived him. Had it been otherwise, after perusing the cases I had published at pages xx. and pages 151, &c. of my Account, &c. he would hardly have thought it necessary to have published more instances of what I had stigmatized as bad practice; or to have sought for further proofs, that an active and useful medicine might be employed so as to prove a deleterious poison.] —"The dose of the dried leaves: in powder, is from one grain to three twice a day. But if a liquid medicine be preferred, a dram of the dried leaves is 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. It is to be continued in these doses till it either acts upon the kidneys, the stomach, the pulse, (which it has a remarkable power of lowering) or the bowels."