The Action of Medicines in the System. Frederick William Headland
CHAPTER I.
INTRODUCTORY REMARKS.
In commencing this Essay on the Action of Medicines, I must confess that I feel at first a certain discomfort when I consider the magnitude of the task before me. Many a volume has been written to elucidate the operations of single medicines, and when the variety and complexity of such an operation is considered, the space devoted to its consideration will hardly seem too great. Thus it is not to be wondered at that, when pausing on the threshold of my subject, I should be sensible of the many difficulties with which such an inquiry is surrounded.
In this introductory chapter it will be my aim, in the first place, to set forth briefly the great importance and extent of the subject, showing that it is an essential requisite in the advance and perfection of medical science. Next, I must insist on the advantage of correctness and clearness of language and argument in the treatment of such topics as this, and show in what manner I propose myself to attain to it. And in the third place, I must shortly explain the scheme or arrangement which will be followed in this Essay. If the preliminary remarks contained in this chapter are not first considered and clearly apprehended, I fear that I may be but imperfectly understood in what I shall have to say hereafter.
There have been, more or less, in all ages, two systems or schools of medical treatment, of which the one prevails among ignorant men, and in rude states of society, but the other requires a higher degree of enlightenment. These are the Empirical and the Rational systems. The first is founded on simple induction. By accident or by experience it is found that a certain medicine is of use in the treatment of a certain disorder: it is henceforth administered in that disorder; and on a number of such separate data an empirical system is constructed. It naturally requires for its elaboration a comparatively small degree of knowledge.
Now this observation of facts is indispensable as a beginning, but something more is required. We must not be satisfied with taking them separately, but we must proceed to compare together a large number of facts, and draw inferences from this comparison. And our plan of treatment will become rational, when on the one hand, from an accurate knowledge of the symptoms of diseases, we are better enabled to meet each by its appropriate remedy, and on the other hand, from some acquaintance with the general action of a medicine, we are fitted to wield it with more skill and effect, and to apply it even in cases where it has not yet been proved beneficial. Thus, for the proper perfection of medicine as a rational science, two things are in the main needed: the first is a right understanding of the causes and symptoms of disease; the second, a correct knowledge of the action of medicines. Should our acquaintance with these two subjects be complete, we should then be able to do all that man could by any possibility effect in the alleviation of human suffering. This sublime problem is already being unravelled at one end. Diagnosis and Nosology are making rapid strides; and perhaps we shall soon know what we have to cure. But at the other end our medical system is in a less satisfactory condition; and though some impatient men have essayed, as it were, to cut the Gordian knot, and have declared boldly on subjects of which they are ignorant, yet it must be confessed, that in the understanding of the action of medicines, and of their agency in the cure of diseases, we do not so much excel our ancestors. While other sciences are moving, and other inquiries progressing fast, this subject, so momentous in its applications, has, in spite of the earnest labours of a few talented investigators, made after all but small progress. Let but those who feel this want bestir themselves to remove it, and it will soon be done. Those doubts and difficulties, which are now slowly clearing away before the efforts of a few, will then be finally dispelled by the united energies of all; and instead of our present indecision and uncertainty on many points, we shall find ourselves eminently qualified to wage the conflict with disease, being skilled in that science whose name bespeaks its peculiar importance, the science of Therapeutics.
The subject assigned to me as the text of this Essay concerns this problem:—"On the mode in which Therapeutic Agents introduced into the stomach produce their peculiar effects on the Animal Economy." It is naturally a subject of very great extent; and one difficulty with which I am beset is that I scarcely know how to compress what I have to say on the action of medicines into the compass required. It will be granted that it is an important subject; it is also a difficult one. This difficulty depends mainly on the variety and complexity of the proof required to establish any one point with absolute certainty.[1] A long time ago, when men knew and understood less than they do now, it was fancied that the action and choice of medicines was a thing of the utmost simplicity; that it was comparatively an easy matter to fix at once upon that remedy required most in any particular case.[2] But the light of science, which in this day burns more brightly, at the same time that it displays all objects with greater distinctness, discloses to us also many dim vast tracts in the distance, of which nothing had been seen or imagined before. In this, as in other things, the more we know the more we discover our real ignorance. It is wrong, then, to treat dogmatically of matters that we cannot comprehend; and when perfectly in the dark as to the operation of a medicine, we should rest content with declaring the result of that operation. This by itself will be of great use to us.[3]
I am induced to lay stress