III. I come now to consider the best method of preparing the body for the small-pox. This must be done, 1st, by DIET, and 2dly, by MEDICINE. The DIET should consist chiefly of vegetables. I have never seen any inconvenience from the free use of milk, as a part of the preparative diet. In some habits, where a morbid acid prevails in the stomach, we may indulge our patients in a little weak flesh broth two or three times a week with safety. A little salted meat may likewise be taken daily in such cases. Tea, coffee, and even weak chocolate, with biscuit or dry toast, may be used as usual, by persons accustomed to that kind of aliment. Wine and spirits of all kinds should be withheld from our patients, during the preparation. The more acescent their drinks are, the better. It is unnecessary that this change in the diet should take place till a day or two before the time of communicating the disease. The system accommodates to a vegetable and low diet in the course of three weeks or a month, so as to defeat in some measure the advantages we expected from it. The good effects of it appear to depend in a great degree upon the _suddenness_ with which we oblige our patients to conform to it. For this reason, when we are called upon to inoculate persons who have lived more than three or four weeks upon a low diet, we should always direct them to live a few days upon animal food, before we communicate the disease to them. By these means we may produce all the good effects of the _sudden_ change in the diet I have already mentioned. 2. The MEDICINES most commonly used to prepare the body for the small-pox are antimony and mercury. The latter has had the preference, and has been given in large quantities, under a notion of its being a specific antidote to the variolous matter. Many objections might be made to this opinion; I shall mention only three. 1. We often see the disease in a high degree, after the system is fully impregnated with mercury. 2. We often see the same salutary effects of mercury, when given before the disease is communicated to the body, that we perceive when it is given after inoculation; in which case we are sure the mercury cannot enter into the mixture with the variolous matter so as to destroy it. 3. If mercury acted specifically in destroying the variolous matter, it would render every other part of the preparation unnecessary: but this we know is not the case, for the neglect or improper use of the vegetable diet or cool regimen is often attended with an extraordinary number, or virulence of the small-pox, even in those cases where mercury is given in the largest quantity.