false in its superstructure, what harm can result from putting it to the test, and ascertaining the fact demonstrably? None whatever, but, on the contrary, much good. We shall at least have gained the power of giving a direct and authoritative negative to its allegations, which we shall then prove to be fallacious, and which have been suffered to reign and diffuse themselves for thirty years from the absence of direct counter-evidence by which to rebut them. We shall thus be able also to put the profession and the public on their guard with some chance of being listened to, and shall have obtained the inestimable advantage of keeping our own minds open to the admission of new truths, and of showing that in our estimate of evidence, and in our conclusions, we are actuated not by any mean jealousy or dogmatic assumption of authority, but by the single and simple desire of advancing the interests of science and humanity to the best of our ability. The very worst that can happen in the event of its being wholly untrue is, that we shall have bestowed some time and pains in obtaining the means of more effectually putting down a great error; while, as a compensating advantage of no small value, we shall have at once increased our knowledge and cultivated and strengthened our intellectual and moral faculties, by the very nature of the mental exercise which such a scrutiny requires; and surely these will be rewards well worth all the time and trouble which they may cost us.

If we adopt the supposition that homoeopathy embodies an admixture of truth and error, the inducement to institute a rigid and careful inquiry into its claims becomes still more imperative, that we may obtain possession of the one and carefully avoid the other. The degree of success, be it more or less, which all admit to attend homoeopathic practice, as conducted by such men as Fleischmann, is sufficient to show that either the system or its advocates possess some advantages in the treatment of disease, which it would be useful for ordinary practitioners also to examine and adopt. Whether the means which afford these advantages be derived from the domain of hygiène, of materia medica, or even of the imagination, is of comparatively little practical consequence, provided their utility to the patient and the best mode of reproducing and applying them to the treatment of disease can be clearly established. This, however, can be done only by careful investigation; and that such investigation would be amply rewarded may fairly be presumed, from the good already effected by homoeopathy in demonstrating the evils attendant on that over-active medication, which characterizes so much especially of English practice. Ordinary medicine is now not nearly so heroic and undiscriminating in the use of strong measures as it was some years ago, and this improvement is unquestionably due in part to the progress of homoeopathy, as well as to the natural increase of our knowledge.

The remaining, although unlikely, supposition, viz., that homoeopathy shall prove to be essentially true in its fundamental principle, and consequently fraught with benefits to science and humanity, as its advocates affirm it to be, need not detain us more than a moment If true, how much more shall we then have reason to rejoice that we did not look upon its claims with prejudiced eyes, or reject and condemn it unheard and unexamined! Had Harvey's detractors examined his facts first, and then given their verdict, how different would the results have been to themselves, to him, and to mankind! And yet in our own day the profession acted towards Jenner, and also towards Gall, as if Harvey's name and memory had been blotted from the page of history.

I press all these considerations upon you, not from any particular leaning towards homoeopathy, or any other new and disputed branch of knowledge, but because of the transcendent importance of cultivating science in a right spirit, and offering truth a ready and unprejudiced welcome from whatever quarter it may come. Ridicule and declamation may be rightfully employed to explode errors after they shall have been proved to be so; but they are most

unfit instruments for the primary investigation of truth, and as such ought to be banished for ever from scientific discussion, and a candid spirit of philosophical inquiry be instituted in their room. I have had no personal experience of homoeopathy, and am, consequently, as little inclined to admit as to reject its claims, but I should wish to steer clear of prejudices regarding it. There are perhaps a few analogies in its favour, but its doctrinal expositions embody much that is crude and contradictory, and most of its practical evidence, in the shape of published cases, is rendered nugatory by the same sources of doubt which render so much of professional experience and testimony inconclusive, if not worthless. Sufficient discrimination is not used, or if used not recorded, to warrant much reliance on the alleged connexion between the remedy and the recovery in individual cases. As in ordinary medicine the post hoc is too universally assumed to imply the propter hoc. If I am not mistaken, the more intelligent homoeopathists themselves admit this, and in consequence do not claim belief on the ground of the recorded cases, but affirm that on the contrary rational belief can be produced only by personal and extensive experience. But while I refuse belief I can see no reason for that deadly hostility which many feel towards the principle of homoeopathy. If it be true, such hostility is misplaced and injurious. If false, it is needless and supererogatory; for the hostility will vanish with the non-existence or destruction of its object. And, after all, why should either party delight in representing homeopathy and ordinary medicine as in every respect opposed to each other? In a large proportion of cases the more rational and enlightened men of both parties employ the very same hygienic and general means which we have already seen to act so large a part in effecting recovery; and the chief difference between them relates to the principle on which the requisite medicine is to be selected. The homoeopathist prescribes according to the principle of similia similibus, because experience, he says, proves this to be the safest and most efficacious plan. The ordinary practitioner, on the other hand, prescribes that which rational, or it may be routine, experience has led him to believe the best adapted for cases of the kind before him; and without stopping to inquire whether its action is homeopathic, allopathic, or antipathic. Surely there is no necessary cause of quarrel in all this, but merely results to be tested by careful experiment. True," you may say, "but then the infinitesimal doses are so absurd." They certainly look very absurd; and I at once admit that nothing short of demonstration and personal evidence will ever inspire me with a conviction of their power to do either good or harm. But then all homoeopathists say that it is the principle of similia similibus, and not the dose, which constitutes the essential element in their system, and that the infinitesimals may be discarded and yet the great principle of homoeopathy remain unshaken. This latter, then, is the great fact to be proved or disproved, to settle the question for ever; and why should it not be put to the test? Let experiments be made on a sufficient number of healthy persons with quinine, or any other drug, to ascertain whether it really has the property ascribed to it of exciting certain groups of symptoms in a sound constitution, and after carefully varying and repeating the experiments, faithfully record and publish the results. Surely there is nothing unphilosophical or undignified in instituting such an inquiry, and nothing so difficult as not to be easily overcome by judgment and patience. Having tried their action in health, try the same remedies in the usual doses in the treatment of disease with as much care and discrimination as possible, and again record the results. If the principle holds good, let us adopt it and be thankful we have now a surer guide than before. If it fails, our exposure of its fallacy will tell with tenfold effect, from being founded on direct experience. In the same way with the infinitesimal doses, let us go at once to facts, and leave mere disputation to the idle speculator. All truth is harmonious, and what is true in the one system must harmonize with and throw light upon

what is true in the other, and, consequently, it would be better for science were both parties to endeavour to find out the points of contact rather than those of repulsion. In the very nature of things, certainty or absolute identity of opinion is, and ever must remain, an impossibility; and it ought never to be forgotten that in this respect there is a radical difference between medical and physical science. Physical science is fixed and positive in its principles and in its details, because its facts are always accessible for examination under the same conditions, or under such variations as can easily be traced and allowed for. Medicine, on the contrary, is and ever must be an estimative science, because its facts and phenomena are subject to continual variations from varying states of the body and mind of the patient, which we can neither control nor appreciate with entire accuracy. Its cultivators, too, are men differing in intellectual power, knowledge, skill, and experience; and even if they were all equal, their judgment is constantly liable to be impaired or disturbed by any slight disturbance of health or excitement of feeling, or even by a little extra fatigue, and hence, although its principles are fixed and determinate, because also founded on the laws of nature, the soundness of the conclusions deduced from them for the guidance of treatment must ever depend on the soundness of the estimate formed by the physician of their operation_and influence in the individual case. Very rarely indeed can they be absolute, and hence the wide field for the exercise of sound judgment, skill, and discrimination on the part of the practitioner, and the mischief which may attend a practice founded on mere routine. Hence the forbearance and charitable construction which, as members of a liberal and useful, but most difficult profession, we are bound to exercise towards each other; and for the exercise of which there is, I fear, ample occasion in this very letter. But restrained as I have been by impaired health, as well as by the impossibility of doing full justice within your limited space to a subject at once so extensive and so important, I could not always express my opinions with the precision which I wished, and therefore I must trust to your good sense and right feeling not to give undue importance to any isolated or dubious expression which you may meet with, but to adopt that meaning which is in accordance with the general spirit of my remarks. My only anxiety has been to help you in the good work to which you have dedicated yourself with so much zeal, energy, and talent, and for which you will, I have no doubt, one day have your reward in a rich harvest of useful results.

I remain, my dear sir, very sincerely yours,

ANDREW COMBE.

P.S. To prevent the recurrence of a very common mistake, may I be allowed once more to call the attention of your readers to the broad distinction which subsists between the principle of similia similibus—which alone constitutes the basis of homeopathy-and the doctrine of the infinitesimal doses, which has been engrafted on, but does not constitute a necessary part of it? This caution is the more required, because the two propositions are more frequently confounded than distinguished, and we are surely bound to take the word in its correct meaning, as used by Hahnemann and his followers.

In a practical point of view, also, it is important to note the distinction, because, while it would be comparatively easy to verify the specific powers or mode of action of any drug given in ordinary or appreciable doses; and thus to test the real principle of homoeopathy, it would be far more difficult and require a much longer and more varied inquiry to obtain precise and conclusive proofs, were the same drugs to be administered in doses altogether inappreciable to sense, as in the decillionth of a grain. We ought therefore to begin with the most important part of the inquiry first, and to leave the doctrine of the infinitesimal doses to be tested in its turn, if need be, after the viability of its parent shall be decided.

A. C.

III. ON THE METHODS FOR OBTAINING A NATURAL HISTORY OF

DISEASES.

BY THOMAS LAYCOCK, M.D.

IN A LETTER TO THE EDITOR.

York, Feb. 13th, 1846. MY DEAR SIR,-When I received the reprint you were so kind as to send to me of your admirable article entitled " Homœopathy, Allopathy," &c., I had already read it in situ with unmingled satisfaction. In compliance with the request you make on the fly-leaf for the opinions of your friends on the matters discussed in it, I send these to you with a very sincere and humble quantum valeat, and with a wish that they may aid in the reformation you seek.

I would here, as a general preliminary, and once for all, make a thousand apologies for any dogmatism or too confident expression of opinion that I may appear to be guilty of. Indeed I would rather make ten thousand here (if you think ten thousand necessary) than occupy your time and patience with a premonitory palaver and kotoo at every notion I may express. So you will really and truly understand that I dissent, assent, and assert with some diffidence and with humble deference to you especially, and to everybody else in general.

In the first place, then, I fully agree with you in all your propositions; I differ with you in two or three minor details only. With regard to proposition 4,* I advance as the result of my experience in vital statistics, that the numerical method is one not as yet generally applicable to medical observations; or, if generally applicable, only in points of detail so simple in character that they scarcely require it for their elucidation, except to those who wish for a numerical expression of facts. In the first place you want skilled observers; you want a regiment of trained men-trained, too, in the same school, at the same drill-so that, whether their observations be right or wrong, they will be alike right and wrong. You know well the difficulty of minute diagnosis; how much skill is required to tabulate effectually according to the inductive method (for this is the true principle of the numerical method) those cases of which you have no doubt; and under the most favorable circumstances for observation how many links in the chain of phenomena to be observed and classed cannot be made out at all. Pray observe I am not giving an opinion adverse to the numerical method, because I am sure it is a truly scientific method. What I advance is, that as yet it cannot be made generally applicable.

Another minor detail I object to is in proposition 19. You would abolish the practice of keeping and preparing medicines in the houses of practitioners. You never could do it. I have lived and practised in both rural and civic districts, and I give this opinion also as the result of experience. Thousands of practitioners will give you the same opinion. A much better arrangement would be to require every practitioner, whether physician or surgeon, living half a mile from a druggist's shop, to keep and prepare medicines in his house. Compel him to do it by law, that the health and comfort of his neighbours may be consulted-things they, at least, estimate more highly than his own sham notions of dignity. It is the selling of drugs and the drugging system that lowers the practitioner in public estimation. He might keep a warehouse full of drugs, and welcome, if he gave them all away, as he ought to do.

Nevertheless there is the germ of a right good reform in proposition

"The general adoption by practitioners in recording their experience of the system known by the name of the Numerical Method is essential to the attainment of the ends proposed in the preceding paragraph, as well as in many that are to follow."

XLII.-XXI.

.16

19. If generally adopted, it will give a heavy blow and great discouragement to the sectarian bigotry of medical men. The " pures" and the impures will be well mixed, and a glorious tertium quid will be the result of the operation. In Thomas Carlyle phrase, strong symmetrical forest trees will grow up, instead of clipped Dutch-garden dragons. Here an oak (a sound-headed, omniscient pure), there an ash, here an elm, there a wide-spreading beech (some Nestor of the general practitioners), or a chesnut; but all graceful, symmetrical things, each supporting each other when the storms come. Of course there will be stubble and brushwood-quacks and humbugs-but even from these may be extracted some good. If there be no good in them, then they are unavoidable evils under all circumstances, and must therefore be endured. Proposition 17 is, I think, rather too strongly expressed.*

Having specified the objectionable points, I ought now in justice to specify the more valuable. This, however, is not an easy business. All the proposi tions contain pith and marrow. Perhaps the first is the most pithy; at least I shall stop at the first. We are to "attempt to establish a true natural history of human diseases." As this is what I have been trying to do for some time, I will give you my views as to the method most likely to be successful. I premise, however, a special and very low "kotoo."

It is essential to the natural history required that there should be-1, a system of observation; 2, a system of classification. You cannot take up jumble of observed things (such a jumble, for example, as the homœopathic cases), and by the mere force of labour in inductive analysis and synthesis deduce useful results. There must be a guiding thread of theory-a centre round which the facts may crystallize-an idea which shall determine the sides and angles. Well, then, as disease is an aberration from normal structure and function, a history of normal structure and function, or in one word the science of physiology must be the basis of your natural history of disease. You cannot adopt any other usefully or safely. Any other will lead you into the empiricism from which we want to escape.

The classification of diseases should, I think, be founded on both structure and function, but mainly on structure. Function is often dependent on structure. Structure, too, really varies less than function, and is therefore better adapted as a basis for that "more comprehensive and philosophical system of nosology" which you recommend in proposition 15. The mucous and serous tissues are those which present the strongest points of difference, and have been often adopted by taxonomists. My own method has been to take the embryological development of the tissues as the guide to observation and classification.

Twelve or fourteen years ago the blastoderma, or germinal membrane, was described as forming two layers of granules. From the outer of these (termed the serous layer) the nervous, osseous, muscular, and tegumentary systems of the body were said to be developed. The other or inner layer, situated next to the yolk, was termed the mucous layer. Between these, or from these, it was reported that the vascular layer was formed. From the combined changes which these two undergo, it was said the intestinal, respiratory, and glandular systems owe their origin. All these views may not be true, but the facts so described had the merit to me of being both useful and simple. I thought they formed a capital basis of classification. I was thus enabled, in treatment, to consider

"No systematic or theoretical classification of diseases or of therapeutic agents ever yet promulgated is true, or anything like the truth, and that none can be adopted as a safe guide to practice." Some kind of guide is safer than no guide whatever; a classification of diseases is simply a methodical arrangement of past experience: this is always a comparatively safe guide.

+ "To endeavour to ascertain, much more precisely than has been done hitherto, the natural course and event of diseases, when uninterrupted by artificial interference; in other words, to attempt to establish a true natural history of human diseases."