Perhaps there is no one thing in medical practice in which failure is so common, as in the accurate proportioning of remedies to the condition of each case. A physician may discover very clearly the nature of the malady, and decide with great correctness upon the appropriate medicines, and yet, may err after all in applying these medicines in the proper amounts, and at the proper intervals. The variations, in these respects, required by different cases, have a wide range—some demanding large doses to produce the needed effects, and others being strongly affected by small ones. In some cases of severe pain, for example, very large doses of opium in some of its forms are necessary to give relief; while, in other cases, in which, perhaps, the pain is by no means slight, quite small doses accomplish the purpose. Similar variations in the quantities of remedies, are required by other circumstances, which are less obvious in their indications on this point, than so palpable a symptom as pain is. The contingencies on which these variations depend, are often, indeed, so uncertain and so secret, that they elude the most watchful and patient investigation, much more that which is hasty and careless. Experience gives to the shrewd and judicious physician a sort of tact in detecting these contingencies, and in so modifying his practice as to meet with some good degree of fitness the various indications which they present. This tact is to be acquired at the bedside of the sick, by patient watching of the workings of disease, and of the influence of remedies upon it; and though the experience of others is a valuable auxiliary in acquiring it, it is only an auxiliary, and cannot communicate it alone. There are a thousand little things that are observed in watching disease from day to day, which materially influence the physician in the details of his treatment, but which it is impossible to record in the history of the case. It is therefore peculiarly true of the wise and skillful physician, that when he dies much wisdom will die with him. And the student of medicine always finds, when he comes to actual practice, that disease, in the sick chamber, is a very different thing from what he supposed it to be when listening to descriptions of it in the lecture-room. One of the first lessons that he learns is, that the long troup of maladies, arranged in the syllabus of the professor, gives but a faint idea of the various and Protean shapes of disease, as they appear before him, in all their complications, with mingled and confused lineaments, instead of the distinct ones with which they are necessarily described in books and lectures. He sees that the general principles which he has learned, are to be applied with almost endless variations; and that a searching and ever-vigilant observation is needed to apply them aright.