* Library of Medicine, vol i. p. 174.

5. Certain morbid conditions of the body, or the intensity of the disease, must, of necessity, greatly modify the action of the remedy. Illustrations of this are constantly met with in practice. It is well known, for instance, that in severe spasmodic affections, large and repeated doses of Opium are borne without a single ill consequence; doses which, if administered under ordinary circumstances, or in milder cases, would almost prove fatal. Again, if we look at Mercury in suppurative inflammation of the liver, or in yellow fever, we find a quantity of Mercury that is sufficient, in ordinary cases, to salivate a dozen men, produces no perceptible effect whatever. The tolerance of bleeding in some forms of acute inflammation, of Tartar Emetic in Pneumonia, and of Calomel in Cholera, may also be mentioned as examples; but perhaps the disease which exhibits the greatest tolerance of medicines is Tetanus. In a case quoted by Dr. Bennett,* a patient, labouring under this disease, took, in the course of ten days, no less than four pounds, seven ounces, and six drachms of Laudanum, besides six ounces, four drachms, and 45 grains of solid Opium. We are not informed whether the patient recovered. Stimulants have also been given to an almost incredible extent, without producing any ill consequences, or even a marked effect on the system; thus Dr. Currie mentions a case of Tetanus, in which the patient took 140 bottles of Madeira in less than a month; the daily quantity being four or five bottles of wine, besides brandy, ale, two gallons of strong broth, and two drachms and a half of Laudanum. The patient recovered. Purgatives appear to make even less impression. In a case recorded by Dr. Briggs,* the patient took, in 48 hours, 210 grains of Scammony, 89 grains of Gamboge, an ounce and four scruples of Jalap, two pints and a half of infusion of Senna, and eight grains of Calomel! Decided benefit is stated to have followed this treatment.

* Library of Medicine, vol. v. p. 243. Medical Reports, vol. i. p. 148.

6. A deranged condition of any of the principal functions of the body modifies and interferes with the operation of medicines. This is peculiarly observable in the digestive organs; when these are the seat of functional derangement or organic lesion, medicines whose operation on the animal economy is mild and beneficial otherwise, may be rendered either prejudicially irritant or perfectly inert. Under these circumstances, Quinine ceases to act as an antiperiodic, Digitalis as a diuretic, and tonics, instead of imparting tone and vigour, are converted into distressing irritants.