In bringing this subject before the Section it is not the object or aim of this paper to consider the relative value of this salt, but to present a summary of how we stand in regard to the advantage which may be derived from the application of it to the cure of disease. Singleness of action in a drug is as valuable as singleness of purpose in a man. The profession has become tired of empiricism; it is anxious to know the pathology of disease, because its therapeutics can then become rational. Permanganate of potash is, as you all know, a dark purple prismatic crystal, freely soluble in water, forming a rich purple solution. It is often objected that permanganate of potash is so quickly decomposed on coming in contact with organic matter that its action is feeble and transitory; this objection can not be maintained, as in reality a