ACTION ON URINARY APPARATUS.— Under certain conditions digitalis seems to increase the flow of urine without altering, in any essential respect, the quantity or proportion of its solid in gredients; but, strange to say, this ac tion is seldom manifested in the healthy human subject, though it is apt to be very pronounced when there is an accu mulation of fluid to be removed. In truth, the manifestations of digitalis are often inconsistent and varying as regards renal secretion, and are probably in great measure indirect and secondary. As before intimated, the infusion is the most reliable form to exhibit for such purpose, and doubtless here the watery menstruum should receive a due portion of credit. That the drug is, in any sense, adenagic or a stimulant to glandular tis sue, and consequently diuretic because of such action, receives little credence these days. A fairly free use of alco holics in connection with the infusion seems to enhance the activity of dig italis as regards the kidneys, but a better method is to combine with the latter a minute portion of eantharides.
Digitalis has no pronounced constant effect upon nitrogenous elimination. Alexeevsky (St. Peter., Inaug. Diss., '90).
The drug increases the consumption of the chlorides, sulphates, and phosphates. Beljakow (Schmidt's Jahrb., B. 219, '91).
Digitalis increases the amount of solids eliminated. in the urine, except urea and uric acid, which are diminished under its use. Biddle ("Mat. Med. and Therap.," '95).
Conclusions regarding physiological and therapeutic actions of digitalis and of its active principles summarized as follows: 1. The physiological action of digitalis is exerted chiefly (a) on the heart, (b) on the blood-vessels, and (c) on the secretion of urine. 2. Its action on the heart is that iL (a) slows the car diac beats chiefly by stimulation of the roots of the vagus in mammals, (b) in creases the force of systole, and (c) in creases the extent of expansion in dias tole. Both b and c are due to an action on the cardiac muscle. 3. IL contracts
the peripheral vessels, and thus slows the current of blood through them. 4. By its combined action of contracting the peripheral vessels and of increasing the power of the heart it raises the blood pressure. 5. The diuresis which digitalis produces is chiefly due to increase of blood-pressure. O. Digitalis contracts the arterioles in the kidney. sooner than those in other parts of the body. The renal vessels may contract so much as to arrest the secretion of urine altogether, although the general blood-pressure is high. 7. When blood-pressure is already high, digitalis cannot be expected to have a powerful diuretic action; but if the blood-pressure be low, from natural con stitution or disease, digitalis will have a diuretic action. S. Digitalis is a local ancesthetic, but also produces pain. It therefore belongs to the class termed by Liebreich "aruesthetical dolorosa." 9. In large or in accumulated doses it gives rise to gastric irritation. 10. The action of digitalis is due to digitalin, digitalein, and digitoxin. These principles all have an action similar in kind, but differing in degree. 11. The therapeutic actions of digitalis and of its active principles are that they (o) regulate the heart's action, (b) assist a failing circulation, and (c) act as diuretics. 12. The regulating ac tion of digitalis is useful in palpitation and functional disturbances of rhythm. 13. The most important use of digitalis and of its active principles is in the treatment of mitral incompetence due either to disease of the valves or dilata tion of the ventricle. 14. In cases of aortic regurgitation digitalis is (a) un necessary and not without danger when compensation is complete, but (h) very useful when compensation fails. 15. When the blood-pressure is already high, digitalis may be injurious by increasing it still farther, and thus causing symp toms of angina pectoris or tending to produce apoplexy. T. Lauder Brunton (Inter. Med. Congress; Brit. Med. Jour., Sept. 29, 1900).