The reader has seen that there are then _five_ ways of judging of the skill and the attainments of a physician. 1st. By examining his opinions on medical subjects, and the reasons upon which they are based. 2d. By observing his practice, and comparing its results with those of the practice of others. 3d. By inquiring into the evidences of his education. 4th. By observing the unbiassed opinions entertained of him by his medical brethren. 5th. By observing his mental qualities as they are exhibited in relation to those subjects which the observer himself understands. If the inquirer be a physician, he can very properly make use of the two first-named means of arriving at the estimate. But if he be a non-professional observer, he must for the most part give up these means, as being liable to lead him into error, and resort to the remaining ones. That he should _entirely_ give up the two first means I do not claim. All that I claim is, that he should place very little reliance upon them, while his chief reliance should be upon the three last. If intelligent men would adopt the course which I have indicated, in their attempt to estimate the professional merits of physicians, they would for the most part avoid the errors which they now so frequently commit. But, as it now is, they very generally form their judgment from a direct observation of medical practice, and from the reports which their friends and acquaintances give of their observations; and they make but slight use of those means of judging, which I have shown to be the least liable to error. And I fear that they will be slow to change in this respect, for the simple reason, that they will be slow to admit their incompetence to sit in judgment on modes of treating disease. Dr. Beddoes, an eminent English physician, once remarked, that “there are three things which almost every person gives himself credit for understanding, whether he has taken any pains to make himself master of them or not, These are: 1. The art of mending a dull fire: 2. Politics: and 3. PHYSIC.” And this is especially true of the last of these. Both the well informed and the ignorant seem to think, that they are perfectly competent to decide whether a physician is treating a case properly; and watch the effect of remedies in order to do this, and hesitate not to express their opinions on this point in the most positive manner. So common and inveterate is this habit in the community, that it will be difficult to eradicate it. And yet I think it can in some good degree be done. Intelligent men can be made to see, by a candid exposition of the peculiar liability there is in medical experience to mistake in regard to the relation between cause and effect, that it requires an extensive knowledge of medicine to make accurate observations of the influence of remedies; and that therefore one who has never studied this science, and who has had but limited means of observation, must