Had he examined them by the microscope, and selected the appearances so elicited as grounds for his classification, it would have been much less useful. In the first place, comparatively few persons would have had the opportunity or taken the pains to _observe_; and secondly, we should have had the inconveniences resulting from that variety which we generally find in the reports of microscopic researches. There is just now a great disposition for microscopic inquiry, perhaps somewhat too much; but no channel should be neglected, if it be not too exclusively relied on. Abernethy amused himself at one period in examining ultimate structure by the microscope; but he seems to have had but a very measured reliance on this mode of investigation. Judicious nomenclature is of immense importance in the framework of science, and a want of care in this has probably done as much as anything to impede the course of rational investigation. There is nothing, perhaps, in the whole range of science more to be lamented than many—indeed, I might say all—parts of medical nomenclature. If our ignorance prevents us from giving a name to a thing which is descriptive of its nature, we might easily avoid applying such as are calculated to mislead. We can imagine the confusion which would result from a druggist labelling a bottle of water, "poison;" and a vessel containing poison, "water;" yet we doubt whether he would more imperfectly express the true relations of these fluids, than the terms "fever" and "inflammation" do the real nature of the conditions which they are employed to designate. Abernethy's arrangement of tumours not only illustrates his disposition to seize on the more salient points of a subject, but also his inclination to seek for the essential relations of (so-called local) disease in the general condition of the body. He consistently, therefore, mentions them in an order founded on such relations. He places those first which he had found least dangerous in their nature, least destructive in their effects, and which appeared to him to have been attended by the least disturbance to the general economy. In like manner he placed those which had manifested more malignant or dangerous characters, in the order of their severity; inferring their characters respectively from the disturbance of the constitution, the resistance of the disease to treatment, and the variety of structures destroyed in its progress.