As a Diuretic, digitalis would hold very high rank, even were its power of relieving cardiac embarrassment unknown. In nearly all varieties of dropsy, except those where there is aortic regurgitation and very great cardiac hypertrophy, this drug is of the greatest service; it is wholly free, also, from the tendency to irritate the kidneys by which many so-called diuretics defeat their own immediate end, besides inflicting further mischief in cases where the kidney is either already diseased or mechanically compressed by ascitic fluid. The diuretic action of digitalis is also especially valuable in purely dropsical hydrothorax, and in those more passive kinds of pleuritic effusion which most nearly approach the character of the dropsical exudate. In all such cases there is a very good prospect of effecting a speedy resorption of the fluid by the use of digitalis in the manner just now described.

The Sudden Suppression of Urine, which occurs in young persons after scarlatina, or from simple exposure to cold and damp, is doubtless to be looked upon as part of a catarrhal inflammation of the uriniferous tubes, which requires little more than a few days' rest in bed, with almost a certainty that the urinary secretion will reappear. In this simple form the catarrhal inflammation scarcely needs the use of a diuretic; but should danger threaten, digitalis is still far preferable to any other drug. It is a different matter when, in the course of a chronic Bright's disease, in which many of the other organs have probably become impaired, a sudden suppression, induced by cold or any other cause, takes place. Here it is clearly advisable to resort to direct measures for the restoration of the urinary secretion, and digitalis is again one of the best agents for the purpose.

As the diuretic effect of digitalis in disease is very different from any effect which it is capable of producing in health, it may be well to consider the probable nature of the action. The idea that this consists merely in the heightened arterial pressure and the swifter blood-current (which, as already explained, exist simultaneously with slackened heart-pulsation) will not bear investigation; for, on that supposition, a constant effect of digitalis (in certain doses) on healthy persons would be diuresis, but such is not the effect. It appears evident that the presence of venous hyperaemia, with or without actual dropsy, is necessary to the production of anything like marked diuresis by digitalis; and the opinion of Legroux and others, that digitalis necessarily compels increased urination by virtue of the heightened arterial pressure which it causes, must be set aside.

In Febrile Diseases, digitalis has been largely employed of late years, especially in Germany. It is not easy to say who deserves the credit of first observing the power of digitalis to lower the human temperature;1 but the first considerable steps in the use of the drug for this purpose were taken by Traube (in 1850), and from that time forward Germany has contributed a constant succession of observations on this subject.

The original paper by Traube announced a number of conclusions, physiological as well as therapeutical; the former of which there is no need to repeat, as I have already given the drift of his opinions. The therapeutical bearing of Traube's researches amounts to this: That, in the first place, digitalis as a stimulant to the regulating cardiac nervous system, diminishes the lateral pressure in the blood-vessels, and also the rapidity of the blood-current, and simultaneously lowers temperature. And, secondly, that by virtue of these actions, it limits the inflammatory process. It has already been shown in my discussion of the physiological action of the drug, that, though Traube was probably right in ascribing a portion of the action of digitalis to its effects on the vagus, it is impossible to account for the whole of its effects in this manner; and, in two important particulars, Traube was certainly wrong. The arterial pressure is not lowered, but heightened; and, as stated above, this heightening of arterial pressure is probably of great service in a therapeutic point of view. Secondly, although the pulse is undoubtedly slowed by moderate (therapeutic) doses of digitalis, there is great reason to think that the blood-current is rendered more rapid - a phenomenon which, since the re-researches of Edward Weber and of Ludwig, is easily intelligible. Traube was right, however, as to the influence of digitalis in lowering temperature, and diminishing the intensity of inflammatory and febrile processes generally - at any rate for a time. The treatment of pyrexial diseases of all kinds with digitalis has become very widely spread on the Continent, and has found a few followers in this country.

Leaving the subject of acute inflammations aside for the moment, we may refer to the remarkable manner in which digitalis has been pushed, especially by German physicians, in the treatment of typhoid fever, typhus, erysipelas, pyaemia, rheumatic fever, and other general constitutional fevers. The plan of reducing high temperature by cold bath has, it is true, to some extent, overridden the use of drugs for this purpose; nevertheless, some of the most enthusiastic supporters of the bath-treatment insist on the great value of digitalis as an auxiliary - as, for instance, Liebermeister, in the remarkable treatise founded on his experience of typhoid fever in Basle. The doses there given have been very large. Traube commonly employed as much as two grammes (31 grains) of the powdered digitalis leaves in twenty-four hours. It seems clear that doses that were unnecessarily large have been employed, and very probably the mortality has been rendered needlessly high. E. Hankel reports that in an epidemic of true ex-anthematic typhus observed in the Leipzig Klinik, eighty cases of the disease were treated, the ordinary dose of digitalis being 47 to 62 grains per diem, but as much as 100 grains being occasionally given. There were thirty-five deaths; and although Hankel explains this immense mortality by the statement that the type of the disease was uniformly severe, and that twenty-three cases were admitted in a moribund condition, there is nothing very remarkably successful in a mortality of 15 per cent.; and it is difficult not to suspect that some of the patients may have been fatally affected by the large quantities of digitalis that were administered. It is not easy to draw definite conclusions from Hankel's report; but it may be mentioned that, as regards the remote influences of digitalis, such as its power to check delirium, only the milder cases seemed to benefit at all permanently. It appears, also, that the patients treated with digitalis emaciated greatly, and made slow convalescence. Wunderlich 1 especially recommends digitalis in the second week of typhoid fever, when the temperature is high, and the pulse rapid; two or three days of the treatment often produce a fall of 2° or 3° (Fahr.) of the temperature, and thirty to forty beats of the pulse.