16. Bleeding is forbidden after the fifth or seventh day in a pleurisy. This prohibition was introduced into medicine at a time when a fear was entertained of arresting the progress of nature in preparing and expelling morbific matter from the system. From repeated experience I can assert, that bleeding is safe in every stage of pleurisy in which there is pain, and a tense and oppressed pulse; and that it has, when used for the first time after the fifth and seventh days, saved many lives. Bleeding has likewise been limited to a certain number of ounces in several states of fever. Were the force of the remote cause of a fever, its degrees of violence, and the habits of the subject of it, always the same, this rule would be a proper one; but, this not being the case, we must be governed wholly by the condition of the system, manifested chiefly by the state of the pulse. To admit of copious bleeding in one state of fever, and not in another, under equal circumstances of morbid excitement, is to prescribe for its name, and to forget the changes which climate, season, and previous habits create in all its different states. 17. The loss of a sufficient quantity of blood is often prevented by patients being apparently _worse_, after the first or second bleeding. This change for the worse, shows itself in some one or more of the following symptoms, viz. increase of heat, chills, delirium, hæmorrhages, convulsions, nausea, vomiting, faintness, coma, great weakness, pain, a tense, after a soft pulse, and a reduction of it in force and frequency. They are all occasioned by the system rising suddenly from a state of extreme depression, in consequence of the abstraction of the pressure of the blood to a state of vigour and activity, so great, in some instances, as to reproduce a depression below what existed in the system before a vein was opened; or it is occasioned by a translation of morbid action from one part of the body to another. The chills which follow bleeding are the effects of a change in the fever, from an uncommon to a common state of malignity. They occur chiefly in those violent cases of fever which come on without a chilly fit. The hæmorrhages produced by bleeding are chiefly from the nose, hæmorrhoidal vessels, or uterus, and of course are, for the most part, safe. Uncommon weakness, succeeding blood-letting, is the effect of sudden depression induced upon the whole system, by the cause before-mentioned, or of a sudden translation of the excitement of the muscles into the blood-vessels, or some other part of the body. These symptoms, together with all the others which have been mentioned, are so far from forbidding, that they all most forcibly indicate a repetition of blood-letting. I shall briefly illustrate, by the recital of three cases, the good effects of bleeding, in removing pain, and the preternatural slowness and weakness of the pulse, when produced by the use of that remedy.