The metallic salts used as _Anticonvulsives_ are all capable, when taken for some time, of causing a deterioration of the blood. This is most apparent in the case of Lead, which, besides a number of nervous symptoms, tends to bring on a kind of jaundice, with general wasting of the body. Chronic poisoning by Zinc and Copper resembles that by Lead. The symptoms of what is called "Zincal intoxication" were recently described to the French Academy by M. Landouzy of Rheims, as occurring constantly among the zinc-workers. There was sometimes an [oe]dema like that produced by Arsenic. The production of all the known nervous disorders by the presence in the blood of different metallic medicines, gives a strong additional probability to the belief that these disorders, when occurring spontaneously, are in many cases due to the presence in the blood of some unknown poison. Among _Antisquamics_, the last Catalytic order, we meet with Arsenic again. Common Pitch is of almost equal utility in Lepra. It has some action in the blood, due to some one of its bituminous principles; but this action is not well made out, or understood. Sulphur, besides its use externally in Scabies, is administered internally with advantage both in this and some other skin diseases. It effects changes in the blood, inasmuch as it is found to combine there both with hydrogen and oxygen, and to carry them out of the system as sulphuretted hydrogen and sulphuric acid. Dr. Pereira and others ascribe to Sulphur a resolvent and liquefacient action. Thus it is sufficiently shown that all of these medicines work out a certain process or operation in the blood, and affect the condition of that fluid. But I am very far from believing that this known operation is in all cases the one by which they neutralize morbid poisons. This action is probably of a much more inscrutable character. Before proceeding further, I may here take the opportunity of insisting again on the differences between Catalytic and Restorative medicines. Catalytics will even in health work out their peculiar process in the blood. Restoratives exercise in that case no particular influence. The latter may remain in the blood; their office is supply or substitution. Catalytics may not remain beyond a certain time; their office is counteraction. The system then labours to excrete them. Before passing out of the body, one or two, as Colchicum, may act on the nerves. In the moment of excretion, the majority act as Eliminatives. But some, as the metals used as Anticonvulsives, are astringent, and diminish secretion generally. Mercury, Antimony, and Iodine, are among the most important Eliminatives known. They act on all glands, but on some more than on others. Antimony is also a special sedative to the Vagus nerve, and as such exerts an important influence, which enables it sometimes to cut short the process of inflammation by depressing the action of the heart. We now arrive at the third minor proposition.