Most of the mercurial preparations will occasionally act on the bowels; but only two are habitually used for the purpose, namely, calomel and the mercurial pill; and of these, only the former can be strictly considered as belonging to the cathartics; the latter being very seldom administered, with a view to its action on the bowels, except in connection with some one or more of the more certain catharthics, which are necessary to secure its effect. We may, therefore, confine ourselves to the consideration of calomel, and of this simply as a cathartic; as upon all other points it has been fully considered already, or will be hereafter.