according to the texture of the part affected, and other cir

cumstances.

The reader is now prepared to see how it is, that mistakes may be made, by confounding the effects of remedies with the changes that arise from the two tendencies, of which I have been speaking. These mistakes have often been committed, even in those diseases which are commonly simple and uniform, and definite in their shape and course. Take, for example, small pox. It was once the custom of physicians to give much medicine in this disease, with the idea that it was controled and lessened by such a course, and the system was thus enabled to throw it off more easily and effectually. But experience has corrected this error, and the physician now stands by, and sees results occur in the progress of this malady without the agency of medicine, which he used once to consider as produced, in part at least, by the drugs that he administered. Let me not be understood to say that no medicine at all should be given in this disease. The office of the physician is to watch it, and if nature, in going through the processes necessary to a favorable termination, needs to be assisted by art, it should be done. But we should be careful not to ascribe to art what is really effected by nature, for we should be led by this error to a too officious interference with her efforts. We may often do much good by medicine-we may moderate the fever, support the strength when languishing, bring out the eruption when it recedes, &c. But to attribute the successful termination of small pox in all cases to the remedies which have been used, would be as great an error as it would be to maintain that the poultices, and other applications made to an inflammatory swelling, are of course the cause of its suppuration and discharge-or, in other words, that they cured the inflammation. All that

can be truly said of them is, that they assisted nature in the And as these applications may sometimes be of too stimulating a character to suit the case, and therefore may increase and extend the inflammation; so the remedies used in a case of small pox, if they be not actually needed, may aggravate the disease. And if the patient recover under such injudicious treatment, it may be supposed that the medicines cured him, though he actually recovered in spite of them, because that same blessed vis medicatrix naturæ came to the rescue.

If there be so much liability to error in a disease so simple and uniform as small pox is, it is still greater in those complaints which are more complicated, from collateral and accidental influences and affections. Perhaps I cannot adduce a better example for our purpose than is to be found in scarlet fever. There is no disease, the history of whose treatment shows so strikingly the uncertainty of medical knowledge and experience as this does. The most opposite and various remedies and modes of treatment have been lauded as successful, in standard medical works, and in medical journals, and multitudes of certain cures have been proclaimed in the newspapers. What is praised by one is condemned by another; and it is the individual experience of every rational and candid practitioner, that a mode of treatment which at one time is attended with marked success at another is wholly unsuccessful. It cannot be otherwise in a disease which varies so much as this does in its degree of severity, in its real character, and in its attendant circumstances. A respected medical friend, in reviewing his cases of scarlet fever, found that he had treated one hundred cases since he had lost a patient with this complaint. But on the very day on which he made this review, he was called to a case of scarlet fever which.

ended fatally, and out of thirteen cases in the same neighborhood he lost seven. With such variations in the severity of this disease, it is very difficult to avoid erroneous inferences as to the comparative success of modes of treatment. This difficulty is increased by the fact, which is remarkable in this disease, that the degree of severity, or amount of danger, is by no means always capable of being measured by the symptoms which present themselves. In the experience of every physician, who has seen much of this complaint, many cases have ended fatally, which, up to within a short period before death, appeared to be doing better than some others in which recovery took place. There was much wisdom in the reply that one physician made to another, who asked ment was in scarlet fever. "I manage each case as strikes me at the time."

him what his mode of treat"I have no treatment," said he. an individual case, just as it. And to this conclusion will ex

perience lead every judicious practitioner.

Let me not be understood to mean that experience, so valuable in the treatment of all other diseases, is nothing worth in this complaint-that it establishes no facts, and no general principles. All that I mean is, that this disease is so variable in its character and tendencies, that extreme caution is necessary in applying these principles, and that the treatment must be at the very antipodes of stereotype-as variable as the disease itself.

I trust that it is sufficiently obvious to the reader that great uncertainty must necessarily rest upon our knowledge of a disease so varied as this is, and that all our experience of the effects of remedies upon it must be thoroughly sifted, in order to attain to any measure of accuracy. It is a disregard of this important truth, that has made the testi

mony of medical men so conflicting in regard to the treatment of this disease.

I need not spend time to show how the same uncertainty must embarrass us, to a greater or less degree, in our investigation of all other diseases. The errors resulting from this source may be avoided, in part, by observing accurately the changes which arise from the two tendencies that we have been considering, their modes, periods, signs, and accompanying circumstances. The efficacy of this precaution against error is, as I have already hinted, in proportion to the simplicity and uniformity of disease. In disorders

which are complicated, and which vary much in their shape and other circumstances, it is exceedingly difficult to decide, how much agency, in bringing about the curative changes, is justly to be referred to the remedies, and how much to the natural energies of the system. Too much credit is very commonly given to medicine, and too little to nature; and sometimes, when some remedy is praised for its efficacy, and the patient and his friends, and perhaps even the physician, think that it has saved his life, it had no agency in promoting his recovery, and perhaps it retarded it.

pass now to the consideration of the fourth class of the causes of the uncertainty of medicine-mental influences. It never should be forgotten in our observation of disease, that we have not to deal with the body alone, but with the body inhabited by a mind, which is connected with every particle of that body by countless nervous filaments, and therefore acting through them upon it, and affecting to a greater or less degree all its diseased conditions.

The influence of causes acting through the mind is often concealed from our view, and even when it can be plainly seen it is difficult to estimate its amount with correctness.

Effects are often produced through the mind, which are attributed by the patient, and sometimes by the physician, too, to some remedy that has been administered. Take a very common case. A dyspeptic, who has contracted his disorder from mental effort, or from the anxieties of business, applies to his physician. He prescribes some medicine, and at the same time recommends him to take a journey, or go to some watering place. He returns cured, and he perhaps gives the credit for the most part to the medicine, or to the medicinal waters which he has drank with scrupulous regularity, either of which may have had little if anything to do with the cure, and relaxation and diversion of mind may have been the chief or sole causes of his recovery. This is a palpable instance of erroneous inference; but we shall have but a narrow idea of the influence of mind upon disease, if we confine our view to cases of so decided a character. Its influence is constant in all diseases; sometimes plain to be seen, as in the case just mentioned; often entirely concealed from the most careful scrutiny; and sometimes revealing itself slightly, so that the watchful eye of the physician catches mere glimpses of it, like passing shadows gone in a moment. Besides the secret griefs and troubles that often hinder recovery, there are varying states of mind, some of which the patient may be hardly conscious of himself, that modify in a thousand ways the movements of disease, and the action of remedies. For example, the cordial which is administered is often in part or wholly neutralized by mental depression, while it is essentially aided in its effects by the genial and animating influence of hope.

The points to which I have alluded the reader will find fully illustrated in the chapter on the mutual influence of mind and body in disease. I will therefore dismiss them for