IN previous communications' I showed that ini physiological quantities there is a mutual antagonism between lime and potash salts, and that through this very antagonism the proper contraction of the heart' is maintained. When lime is unantagonized' by a potash salt, then great delay of the cardiac dilatation ensues, so that before the completion of dilatation another contraction begins. The beats thus become fused and the ventricle not dilating completely, or even very slightly, the amount of

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... ood propelled with each systole is much reduced in quantity and consequently the circulation much retarded. At this juncture a physiological quantity of any potassium salt accelerates the dilatation and carries it to completion before the next contraction begins, and so the circulation is maintained. In this paper I propose still further to develope the antagonism subsisting between these salts, and shall show that lime and potash salts are antagonistic not only in physiological but also in toxic doses. A few years ago an interesting controversy arose respecting the mutual antagonism of drugs. On one side, Schmiedeberg, Heidenhain, Luchsinger, Langley and Prevost maintained that drugs mig,ht be mutually antagonistic, whilst Rossbach denied this statement. The former maintained that the effect of a drug might be antagonized by a second drug, which if increased in quantity would manifest its own individual effects, but these effects could be removed (or antagonized) by increasing the quantity of the first drug. To take an example from Schmiedeberg;-atropin will antagonize the action of muscarin, and muscarin the action of atropin on the heart. To take another instance from Langley;-atropin will antagonize the action of jaborandi on the submaxillary gland, and vice versa, if after atropin hias antagonized the action of jaborandi a further quantity of jaborandi Journ. of Phys. Vol. iii. and iv.