Purging is frequently employed in the cure of inflammation, especially such purgatives as are called cooling, which, in this case, is an imaginary quality; but, unless in so far as they tend to abate the irritation of costiveness, they can do no more than bleeding can, and are, in many respects, inferior to it. They are, in one view, to be compared with the application of cold, which is only indicated when there is much heat; both are intended to diminish action, chiefly by removing stimuli from the part to which they are applied. Purging is very uncertain in the effects which it produces on the system, and in the degree of weakness which it causes; and, therefore, never can be put in competition with bleeding, as a general remedy; and, wherever bleeding is improper, or its propriety doubtful, purgatives are still more injurious. They operate likewise so slowly, at least comparatively speaking, that they do not influence the local action so much, as the loss of such a quantity of blood, as would produce an equal effect on the body, will do, unless in particular cases, when they act upon the principle of the sympathy of equilibrium; as, for instance, in pulmonic inflammation, when they sometimes are of service, by increasing the action of the intestines, and diminishing that of the lungs[6]. In the same way, emetics sometimes cure slight inflammation of the tonsils. One of the best and pleasantest saline purgatives, is the phosphate of soda, which may be given to an adult in the dose of an ounce, in order to obviate the effects of costiveness. If we wish to use it, upon the principle of the sympathy of equilibrium, we must give two ounces, or more. The same cautions which were given, with regard to bleeding, apply also to purging. [6] This action is, in this respect, similar to that of blisters.