This section is from the book "A Treatise On Therapeutics, And Pharmacology Or Materia Medica Vol1", by George B. Wood. Also available from Amazon: Part 1 and Part 2.
Certain states of the mind are known, from experience, to have a sedative effect upon the system at large. Grief, anxiety, and all the various modifications of fear are distinguished, in common nomenclature, as the depressing emotions. Whatever, therefore, in any manner counteracts or removes these feelings, must be indirectly stimulant; and, even though purely negative in its operation, would rank among tonic influences. But there are also mental conditions which have a directly elevating or supporting effect. The more refined pleasures of sense and perception; the appreciation of the beautiful, the picturesque, or the sublime in nature and art; the enjoyment attending the legitimate exercise of all our intellectual powers; the pleasurable emotions of love, hope, confidence, joy, of triumphs over difficulties, of temptations resisted, of a legitimate ambition gratified; all these produce in our physical systems an excitation, which, though, like stimulation from any other source, it may be exces -sive and injurious, is more generally within the limits of a healthful influence, and, in states of debility, is positively tonic and restorative. No practitioner can fully perform his duty towards his patients, who does not avail himself of this instrumentality in cases of debility. It is probably more available, in the treatment of defect of function in the digestive organs, the liver, and the brain, than in pure general debility; as it is upon these functions especially, that the opposite condition of mind exhibits most obviously its depressing tendencies.