and health are in immediate dependence upon them; I say, that none of all these things are in opposition to any fact hitherto discovered, either of the medical kind or any other. On the other hand, in all ages physicians have sought for some constitution in the air, inexplicable, and perpetually unknown, to which diseases might be ascribed that could not be supposed to originate from any of its ordinary properties. To explore this constitution is as great a desideratum at the present moment as two thousand years ago; and any attempt to investigate it, or a conjecture relating to it, cannot be supposed inconsistent with any thing already discovered and ascertained. There are many things which lead us to think that electricity is very much concerned in diseases, and among the rest we must account the new discovery of Dr. Perkins’s metallic conductors a very notable proof of it. These, when first ushered into the world, were made by many a subject of ridicule; but the evidence in favour of their efficacy, both in America and in various parts of Europe, seems now to be decisive in their favour; and, if they act at all, it is almost impossible to suggest any other principle than that of electricity to which their efficacy can be owing. No doubt it is difficult to draw the line properly betwixt credulity and skepticism, but where credible testimony determines any thing to have actually happened, or where solid reasoning gives room to suppose any thing to be probable, it never can be invalidated by any argument _a priori_ formed against the _possibility_ of such a thing taking place. In page 128 it is said, that M. Lavoisier, by introducing the new chemical nomenclature, “has entailed the greatest curse upon the science it ever met with.” All apology for this bold assertion is absolutely necessary, and the quotation made from Dr. Ferriar may be deemed inadequate, or perhaps misapplied. In passing this censure on the nomenclature I wrote from experience. The new nomenclature, instead of promoting _my_ improvement in chemistry, hath had a direct contrary tendency. An instance of the inconvenience and ambiguity arising from it is given p. 135, when speaking of Dr. Girtanner’s theory. But a much more remarkable example is to be met with in the review of Dr. Monro’s Chemical Treatise, where we find him censured for the very same ambiguity taken notice of with regard to Dr. Girtanner. “He might have observed (say the reviewers) the distinction between the hydrogen and inflammable air, and between the oxygen and pure air, as well as between the azote and impure air: he has mentioned these as synonimous, whereas they are terms that express bases, or substances in a concrete state (what I have called the condensable part) and the compounds of these substances and heat, when they assume the form of gases or elastic fluids.” (Monthly Rev. for 1790, p. 26.)