with the Physician here, for he knows how easily the public are deceived in relation to facts, and he makes his appeal to results with a bold confidence. The proprietor of a patent medicine points you to his wonderful cures, as the facts which must convince every one of its efficacy and value.

The Homœopathist comes with his little globules, and says, that laugh as you may at the tiny doses, his appeal is to the cures, which he claims they effect as if by magic. Talk with some practitioner who has adopted this mode of practice from purely mercenary motives, and who is rather ashamed of it, ply him with argument to show the fallacy of his doctrines, drive him from one stronghold to another, and, at last, you will come to his citadel, in which he feels perfectly secure from all your shafts. You will be told, with a cool kind of defiance, these are the facts-our medicines cure disease, and the people are beginning to see the truth.

The Hydropathist, too, will point you to narratives of scores of patients cured of all kinds of ailments by nothing but a cold wet blanket, and will say, wonderful as it may seem, these are the results. So it ever has been. The same appeal has been made in behalf of all the delusions that has ever obtained a currency in any community. The Homœopathist and Hydropathist appeal to their facts and their cures, as the sure proof of the efficacy of their practice.

But must the Physician say nothing about results to the public? Certainly he should.

In the first place, he should endeavour to guard those with whom he has daily intercourse against erroneous views of results in medicine, by showing them the difficulties that lie in the way of estimating them with correctness. If he succeeds at all in producing a proper impression upon their minds, and thus inclines them to be modest and careful, instead of being bold and heedless, in expressing their opinions on subjects, he will exert an effectual influence, in preventing them from being deluded by the partial views of facts, and the mis-statements upon which empiricism relies for its

success.

In the second place, whenever he can make a comparison between the results of good practice and those of quackery, which can be fairly understood, let him do it. To warrant such a comparison, the facts should be clear, well-authenticated, and in sufficient number to justify the general conclusions drawn from them.

In the third place, whenever he can show, by facts, which can be appreciated by the common observer, that the practice pursued by any pretender has been entirely inappropriate to any case, especially if this can be done by evidence discovered in an examination after death, let him do it, and explain with all clearness the nature of that evidence to the friends of the patient, and, if necessary, to the community. At the same time, he should avoid joining in with the popular disposition to ascribe death to the treatment pursued as

a matter of course, whether the proof be or be not satisfactory.

There is no doubt that death is frequently the consequence of bad practice, when it cannot be proved to be so; but not even the quack, murderous as his course certainly is, should be condemned upon faulty and defective evidence.

CHAPTER VI.

THEORY AND OBSERVATION.

ALL real knowledge is based upon observation; and it is the facts discovered by observation, which, accumulating from age to age, constitute the store of human knowledge. Not a single grain has ever been added to this store, in all the ages of the world, through the intrumentality of theory alone. Theory, or hypothesis, has often suggested the existence of facts, and has directed in the pursuit after them, but observation after all is the only agent that has discovered them.

Facts are of two kinds-particular and general. General facts are discovered by a careful observation of a great number of particular facts. Thus Newton, by observing many particular or individual facts, established the general fact, which is called gravitation, viz., that all bodies are attracted towards each other, or have a tendency to come together. So in medical science, by an observation of many facts in individual cases, it has

been discovered that there is a tendency in the human system to restoration to health, whenever it is attacked with disease-a tendency, existing as a general fact, to which has been given the name, Vis Medicatrix Naturæ.

These general facts are sometimes termed principles or laws, and are sometimes spoken of as the relationships of facts. A theory, or hypothesis, consists in a supposition of relationships which have not yet been ascertained. Thus Newton, after discovering the great general fact of gravitation, supposed that there might be a sort of ether, connecting bodies together, and acting as the medium of their attraction. This supposition of a relationship, or general fact, not yet ascertained, is a theory, or hypothesis. So when Stahl supposed the principle called the Vis Medicatrix Naturæ to be in the soul, and when Cullen supposed that it exists in the nerves, and produces in fever a spasm of the extreme vessels, they both put forth a mere theory. Cullen speaks of Stahl's theory as being fanciful. It is But Cullen is just as fanciful, if by this word it is meant that it is unsubstantiated by fact. Cullen's supposition is more plausible, it is true, than Stahl's; but it is no nearer being a proved fact.

So.

There is often much indefiniteness in the use of the word theory. Thus the doctrine, or law of gravitation, as discovered by Newton, is sometimes spoken of as his theory of gravitation. It was once his theory; that is, when it was a mere supposition of his mind. But when, by a series of observations it came to be a proved fact,