The living organism possesses a susceptibility to the action of certain general stimuli, such as light, heat, electricity, aliment, atmospheric air, etc. The action and reaction of these stimuli and this susceptibility are the conditions of life. So long as they act upon it in a due relative proportion, as regards intensity and quantity, the equilibrium of the functions is preserved and the organism continues in healthy action. The absolute withdrawal of one of the stimuli for any considerable length to time results in death. A disturbance of their due proportion, in respect of intensity or quantity, produces an abnormal performance of function in the organism- a deviation from health-disease. But these stimuli are continually varying in proportion, or, in other words, the relative susceptibility of the organism is continually changing.
Why doses not disease constantly exist? Because the organism is endowed with either a faculty of provisionally supplementing to a limited extent one stimulus by another, or with a kind of elasticity, a power of enduring for a certain time a disturbance of the equilibrium of these stimuli, and of rebounding to a normal performance of functions again so soon as the natural proportion of the stimuli is restored or the deficiency made up. In this respect, the living organism differs from an inorganic machine, which cannot, in the nature of things, possess any power to endure a disturbance of that equilibrium of forces which is the condition of its normal working without a disorganization from which it has no inherent power to recover.
But, is the organism this elasticity has its limits. This “vis medicatrix naturae” is not inexhaustible. If the due proportion of the stimuli remain too long disturbed, the functions of the organism become permanently deranged at least, to such as extent, that no restoration of the balance of the stimuli will cause a return to their normal performance. The functions are and remain deranged-disease has occurred; or, if we choose to call every deviation from a state of equilibrium disease, then we may say that now disease ensues which has no tendency to revert to health without the intervention of some extraneous influence foreign to the organism and different from the general stimuli aforesaid.
Since, then, the general stimuli will not bring back the organism to a healthy action, a new element must be sought for and introduced, the action of which upon the susceptibilities of the organism may cause a restoration to health. This new element will be a special stimulus. Being foreign to the organism and different from the general stimuli, not only must it act upon susceptibilities in the organism which the latter do not awaken, but the formula which shall express its relations to those susceptibilities, and which shall furnish the rule for its employment, can never be discovered by a study of Physiology, for Physiology concerns herself with the relations of the general stimuli aforesaid and the general susceptibilities of the organism.
This formula of the relations of special stimuli and special susceptibilities can be discovered only by the application of induction to a multitude of instances of the action and reaction of such stimuli and susceptibilities, and confirmed by subsequent deductive verifications. this formula will constitute an empirical law, which will be the law or fundamental principle of Therapeutics. For the application of special stimuli to the diseased organism is the domain of the science of Therapeutics, while all that concerns the restoration and maintenance of a proper equilibrium of the general stimuli appertains to the science of Hygiene.
These propositions may be more intelligible if illustrated by a reference to daily experience. A healthy man is exposed to an unusual degree of cold; in other words, there exists for him a deficit of heat-one of the general stimuli which are necessary to maintain life. Nature has anticipated variations in the supply of his stimulus from external sources by her liberal provisions of calorific apparatus within the organism. Despite the operation of this provision, he is chilled and suffers from rigors, etc. After a time he seeks shelter, sits by a fire, takes a warm drink; in other words receives from external sources an excess of that general stimulus from deficiency of which he has been suffering. His functions resume their normal play. He is in perfect health. Here the equilibrium of the functions has been disturbed and (if we use terms extreme rigor) disease has been produced, but not to a degree beyond the provisions of the vis medicatric naturae-the natural tendency to a restoration of the balance of the functions. The case was treated upon “general principles” in accordance with the maxim cause sublata tolliture effectus. And this maxim represents, in fact, the great law of Hygiene, viz: that it be ascertained what stimulus has been deficient or excessive in quantity or abnormal in quality, and that the equilibrium of the stimuli be restored.
But let us suppose that the same man has again been exposed to cold, perhaps to a greater degree. He seeks shelter and essays to restore the lost heat, but without avail. Despite the fire and warm drinks, the rigors continue and are succeeded by fever and quickened respiration, cough, etc., or by rheumatic pains, redness and swelling, etc. Why this difference between the case? This case too has been treated on “general principles.” The cause has been removed, why has not the effect ceased? The equilibrium of the general stimuli has been restored and the loss made good; why is not normal equilibrium of the functions re-established.
The normal proportion of the general stimuli, it is true, has been restored, but during the disturbance a new element had been introduced into the problem. The organism had suffered a dynamic and then an organic change. The functions are permanently modified. The general stimuli may henceforth be balanced never so carefully, and in strictest accordance with the rules of Hygiene; the organism will not respond.
Its functions are performed after a new fashion. The organs are not susceptible to the wonted stimuli applied according to the laws of Hygiene. The organism has passed from a state of health into one of permanent disease. The general stimuli which, modified and balanced under the laws of Hygiene, sufficed to steady it as it rocked and swayed in its rapid course along the rough and crooked railway of life, will no longer answer the purpose, for in its rocking it has run off the track, and is now bumping along over the crossties, making headway, it is true, but toward its own destructions. It needs now the intervention of some new agent acting under a new law-of a jack-screw and levers operated by forces from without-to re-instate it on the road of healthy action. The wonted general stimuli under the laws of Hygiene being insufficient new stimuli of a special character must be applied according to a new law. This new stimuli are Therapeutic agents, and the study of the law and of the agents constitutes the science of Therapeutics.
Having thus marked out its limits, we have next to inquire what the nature of any possible science of Therapeutics must be. Its subject is the modified functions and organs of the body. Its agents are special stimuli drawn from whatever region of the external world. By what sort of a formula can these agents be applied to that subject? Can the Therapeutist act on “general principles” as the Hygienist does? Can he act on the maxim cause sublata tollitur effectus? Obviously he cannot.
It so far as the cause of disease can be discovered in external influence, the treatment falls within the limits of the science of Hygiene as already discussed. In so far, however, as the cause of disease is identical with the essential cause of the modification of function or organ which we recognize as the disease, it can never be discovered, for it is the same, in its nature, as the cause of healthy functional or organic action; in other words, it is life itself, the nature of which, as of every first cause, is inscrutable. It being impossible then to ascertain the essential cause of diseases, and to apply a remedy according to the rational method-as the Hygienist does-the Therapeutist is necessarily thrown back from an attempt to investigate first causes, to the study of phenomena and to the adoption of the empirical method. In accordance with this method, the subject of his researches will be respectively the phenomena manifested by the patient, and the phenomena produced by the special stimulus, and his endeavor must be to discover a general formula which shall express a constant relation between these two series of phenomena and shall serve as the Therapeutic law.
In thus acting, and upon this method, he will do precisely what the student of every branch of Natural Science does and has done. For in his inability of find out the essential cause of the phenomena that form the subject of his study, the physician finds himself in the very same predicament as the Naturalist who likewise has vainly sought to discover the essential causes of the phenomena of gravitation, of light, of chemical action, and of electricity. As the physician is unable to discover the essential nature of life and organism, whether normal or modified, to ascertain the cause of health or of disease, and is therefore unable to treat disease upon the principle “tolle causam” (except in matters of Hygiene, as before stated), or “on general principles,” so the Naturalist has been compelled to abandon the rational method, such as Aristotle proposed and philosophers elaborated up to the time of Bacon and Newton, and to adopt an empirical method in which the fundamental principle is an empirical law or generalization expressing the relation between two series of phenomena. The science of Physics, for example, consists of the phenomena respectively of two bodies, or series of bodies, so far as density and volume are concerned, and of the law of gravitation which expresses the relation between these respective phenomena.
The Therapeutist, then, abandoning all idea of constructing a science of Therapeutics on the rational method, must have recourse to the empirical, as the elaborators of other natural science have done. The elements of his science will be as follows: He has to deal with a subject known by its phenomena-the sick body, with an agent known also by its phenomena-the sick body, with an agent known also by its phenomena-the drug; and with a law which shall tell how to apply the agent to the subject for the accomplishment of a a cure, a law which shall express the general relation between the drug and the morbid organism.
The following tabular statement will show more clearly the nature of Therapeutics as a science, and its harmony with other Natural Science; for every Inductive Natural Science (except those of classification) consists elementarily of two series of independent phenomena, connected by the formula of their general relation:
THERAPEUTICS.
Morbid Functions & Organs, Or, Pathology and Pathological Anatomy, Therapeutics Law.
Or. Sick-Phenomena,
Toxic Functions & Organs,
Or. Pathogenesis and Pathogenetic Anatomy,
Or, Drug, Phenomena.
PHYSICS
Phenomena of the Sun, as regards
Volume and Density, Law of Attraction.
Phenomena of the Earth, as regards Volume and Density.
CHEMISTRY.
Properties of Potassa, Law of Chemical Properties of
Affinity and Sulphuric acid.
Definite Proportion.
OPTICS.
Properties of the Law of the Properties of the
Luminous, Body, Diffusion of light receiving body.
Light.
Though thus simple in theory, Therapeutics is in reality the most complex of all the natural sciences. Each of the classes of phenomena requires for its study the aid of several auxiliary sciences. Thus, in order to know thoroughly the phenomena of disease, we must call to our aid Anatomy and Physiology, Chemistry, Physics and Psychology. To know and understand thoroughly the phenomena of artificial disease or pathogenesy, we must avail ourselves of the same auxiliary sciences.
The more imperfect our knowledge of these science, the less complete will be our acquaintance respectively with the phenomena of Pathology and Pathogenesy, and the converse. But, however complete or partial may be our knowledge of these two classes of phenomena, the relation between them, as known, remains the same, and is always expressed by the therapeutics law. The same is true of Physics and of all the natural sciences. Our knowledge of the physical properties of matter is continually increasing. The more complete it is, the more exact will be our application of the law of attraction. But complete or incomplete, the law is equally applicable, and pro tanto available.