Pharmacology, or the Doctrine of Drugs (ψαρμακον, a drug, λογος, a discourse), is the science which treats of the drugs employed in medicine. It embraces, therefore, in its scope, all of Materia Medica and Therapeutics relating to drugs. By a few writers this term is employed in a more restricted sense, so as to include only the physiological action of drugs,—a subdivision of the Materia Medica, and a subject which is more correctly designated by the term Pharmacodynamics, (see below).
Pharmacy is the name of the art which supplements the science of Pharmacology, viz.:—the art of preparing drugs according to the requirements of the pharmacologist, and of dispensing them on the prescription of the therapeutist. It includes a thorough knowledge of the Materia Medica, an acquaintance with the theories and manipulations of chemistry, and an intimate practical experience in many special operations peculiar to itself.
Materia Medica and Therapeutics.
Materia Medica is that branch of Pharmacology which treats of the substances used as medicines, and describes their origin, composition, physical characteristics, chemical properties, modes of preparation and administration, and their physiological and toxicological actions. Its divisions are—
Pharmacodynamics (ψαρμακον, a drug, δυναμις, power), signifying the discussion of the physiological action of drugs,—that is, the modifying power of drugs upon the normal physiological activity of the human organism.
Toxicology, (τοξικον, a poison, λογος, a discourse), teaches of the effects of drugs when administered in poisonous doses; also, of their drug-antagonists and chemical antidotes.
Therapeutics, (θεραπευειν, to attend upon), relates to the treatment of disease, and includes the discussion of all matters relating to the science and art of healing. Not only does it consider the application of medicines to the alleviation or cure of disease, but it embraces the employment of all other agents which are capable of contributing to the accomplishment of that result.
The operations of Nature herself, the actions of the various substances described in the Materia Medica, also those of food, clothing, climate, heat, cold, electricity, and of all other remedial agents, forces, and measures,—are all included in the term Therapeutics, which may be divided into two grand divisions, viz.—
NATURAL THERAPEUTICS, including the operations of the Vis Medicatrix Naturae,—the modes and processes of healing which occur independently of Art, for the spontaneous decline and cure of disease. There is no fact in science more fully established than that the living organism is in itself adequate to the cure of all its curable disorders.
APPLIED THERAPEUTICS comprises the application by Art, of agents foreign to the living organism, for the purpose of aiding Nature to restore the body to a comparatively healthy condition.
When used in connection with Materia Medica, the term Therapeutics is restricted to the remedial uses of those substances only which are generally considered medicinal. When systematically discussed under the various titles of these substances, or under the names of the diseases treated therewith, the matter is termed the Special Therapeutics of a certain article or of a particular disease. When arranged so as to present certain great principles, which may be deduced from the mass of isolated therapeutical observations, it is termed General Therapeutics. Thus we say "the special therapeutics of Arsenic,"—"the special therapeutics of Rheumatism,"—"the general therapeutics of digestion." Other divisions of the subject, constantly referred to in professional conversation and literature, are those designated by the terms Empirical Therapeutics and Rational Therapeutics.
By EMPIRICAL THERAPEUTICS we mean the employment of a drug, or other remedial agent or measure, in a certain case of disease, for the sole reason that some person had previously used it successfully in a case which was apparently identical with the one under treatment. Necessarily the original method in Therapeutics, its reign has continued to the present time, and it is by many authorities lauded as The Therapeutics of Experience, founded on observation and experiment. At best, however, it is utterly unscientific; and would be destructive to all exactness ill therapeutical progress, if permitted to rule unchallenged. It is a mere elaboration of Mrs. A's advice to her daughter, Mrs. B, to give her baby hot saffron tea for the measles, because Mrs. C's great grandmother had brought a family of ten safely through the disease with no other medicinal aid.
RATIONAL THERAPEUTICS is the very antithesis of Empiricism, as it consists in the employment of remedies with a definite object, and for reasons based on known laws of the remedies and of the diseases. When working by this method we administer a certain drug in a certain disease, with a more or less clearly defined idea of the morbid conditions present, and of the modifying action of the drug upon those conditions. Based, as it is, upon pathology and pharmacodynamics, these upon physiology, and it upon chemistry and biology, its progress must be slow, being dependent upon the advances made in all these fundamental branches of knowledge.
A Compend of Materia Medica, Therapeutics, and Prescription Writing, 1902, by Sam'l O. L. Potter, M.D., M.R.C.P.L.