By physicotherapy is meant the use of cer tain physical agents such as heat, cold, light, electricity, etc. Certain forms of application of the agents are termed (a) hydrotherapy (q.v.), in which heat and cold are applied by means of water ; (b) phototherapy (q.v.), in which light is used in the treatment of disease. Sunlight, electric light, ultra-violet rays (Finsen's light), X-rays, radio-active substances — these all exert on the tissues of the body certain influences that, properly applied, may bring about restoration of disordered functions, and thus aid nature in curing disease.
Mechanotherapy is the use of mechanical movements in treatment. Massage, vibration, gymnastics, Swedish movements, etc., are some of the different forms in use. Under the name of osteopathy (q.v.) it is attempted to elevate one of the oldest aids to treatment, in use by the Greeks, Chinese, etc., to the rank of an exclu sive system.
Under the terms pharmacotherapy and surgi cotherapy are included the treatment of disease by drugs, so-called, and by surgical means. So far as treatment by means of drugs is con cerned, it is interesting to note that practically all drugs act on the tissues of the body in some chemical or physicochemical manner. They may have a certain selective action on certain tis sues of the body. Thus the large group of the alcohols, comprising ethers, aldehydes, chloro form, hypnotics — such as trional, sulphonal, veronal, urethane and a large number of others —have a selective action on the nervous tissues of the brain, benumbing their activities and causing drunkenness or anaesthesia or sleep, ac cording to the dose or other conditions. Others act on sensory nerves, diminishing pain; such are cocaine, opium, antipyrin, acetanilid, phe nacetin, cannabis, etc. Again, other remedies are chiefly on the intestines, giving the large group of cathartics, and so the entire list of drugs might be analyzed. Given a knowledge of the selective or generalized action of the drugs, the power that they may exert in correct ing abnormal physiological activities is solely a matter of application and in accordance with the correct interpretation of the cause of the dis turbed functions will the therapeutic applica tion be of direct value or not. In other words, drugs are nothing more than chemical agents which may be used to modify certain physiolog ical activities; if by their well-known power,in modifying these activities other morbid activi ties may be corrected, they are agents for good. For a consideration of surgicotherapy, see SURGERY, HISTORY OF GENERAL.
One other phase of therapeutics remains to be considered. It has been pointed out that nature has resources of her own for overcom ing certain types of disease. Can these natural powers be so played upon or affected as to in crease their operation? Along this fins .new paths have been opened up since the recogni tion of a large class of diseases known as in fectious. Bacteriology (9.v.) has taught that disease organisms (bacteria) cause the disturb ance (disease) in the body not so much by their physical presence as by the extremely virulent poisons that they form. It is the struggle of
the human body to get rid both of bacteria and poisons that makes the disturbance which is called the disease. Thus the diarrhoea of typhoid is one of nature's efforts to throw off poisons; the high temperature and crisis of pneumonia is a supreme effort of the body, which sometimes succumbs under it, to deal a death-blow to the pneumococcus, the micro organism that causes the disease. The high temperature in malaria (q.v.) unquestionably kills off a great many of the parasites in the blood. • But in addition to these larger and more palpable efforts on the part of nature to over come the invader, a series of subtle and intri cate defenses are at work in the blood-serum, some of the elements of which are known. Thus in some diseases there is elaborated in the blood-serum a direct chemical antidote, an anti-toxin, to the poisons of the invading bac teria. Such •a protective power is found in diphtheria (q.v.). (See Vaccina tion, the discovery of which was almost the result of an accident, is a form of serum-treat ment. (See SERUM-THERAPY). The details of the reasons why immunity is conferred by the modified smallpox of the cow are not yet known, as the true cause of smallpox is not indubitably proven, but the time is not far off when the different factors herein involved will be un earthed. A large number of other questions are concerned in this great question of natural and acquired immunity (q.v.).
Human progress has been likened to the advance of a drunken man, and it is certain that the ups and downs and side-lurches and backward steps in the path of therapeutics have been many; but withal there has been a broad blaze of progress. That which has been tried and been found to be true has been grasped and has become the heritage of the whole com munity. The physician class have shared with the people at large in the general movements ; there have been many side-tracks from the broad road of therapeutics; innumerable pathies have had their little day or their 100 years; each in its turn has contributed what kernel of truth it possessed to the progress of the mass.
Bibliography.--Bernheim, 'Suggestive Ther apeutics — Dietetics' ; Hutchinson-Thompson, 'Physicotherapy, Mechanotherapy' ; Cohen, 'System of Physiologic Therapeutics — Phar ; Brunton, 'The Action of Medi cines' ; Cushny, A. R., Pharmacology and Therapeutics' (6th ed., Philadelphia • 1915) ; Forchheimer, F., 'Therapeusis of Internal Dis eases' (2d ed., 5 vols., New York 1914) ; Hare, H. A., 'Modern Treatment' (2 vols., Philadel phia 1911) ; id., 'Textbook of Practical Therapeutics' (15th ed., ib. 1914) ; Schmiede berg, (Arzneimittellehre) • 'Surgery' ; Mikulicz Bruns, edited by W. T. Bull, 'Immunity' ; Roger, 'Infectious Diseases' ; Ehrlich, (Seiten kettetheorie ; Vaughan and Novy, 'Cellular Toxins.'