This range is practically unlimited. The collection of all useful or suggestive facts gathered by genuinely scientific methods from the enormous accumulations to be found in our Government reports, in the records of our medical periodic literature, in the observations of hospitals, societies, cliniques, and private practice, would, if properly arranged and tabulated, form a most useful branch of such a centre. If such collection and examination were extended to the records of other countries, the value as well as labour of the work would be greatly increased. The observation of the dietetic and hygienic as well as medical treatment of disease, including climate, soil, atmospheric conditions, the distribution of disease, the effect of occupations, prenatal influences, and later training, are essential. The action of mineral waters, of compressed and medicated air, the hydration of tissues, the conversion of vegetable into animal tissue, the action of the various constituents of the human body as curative of disease, present necessary subjects of investigation. A careful judicial inquiry into the claims of specific cures, where a sufficient case for investigation is presented (as _Echinacea angustifolia_ in snake-bite, also the Russian bath as preventive of hydrophobia), would form another valuable department. In fact, it is impossible to specify the full range of important subjects which demand the devotion of able and painstaking research, working upon the careful study of each type of life for the benefit and improvement of that type. In no branch of this wide range of inquiry is painful experiment necessary. Our homes, our industrial occupations, our legislative enactments, should all be guided by hygienic knowledge, and its diffusion should be actively encouraged by the community. Our hospitals and dispensaries need to promote practical hygiene. Our medical schools should turn the force of their learning, ability, and great influence to the conversion of their students into a vast body of sanitary missionaries. If our thousands of medical graduates turned out every year into practice could go forth inspired with enthusiasm for health, convinced that the preservation of health was their especial work, and that all disease must be regarded as a violation of the laws of health, a violation which it was their special duty to fight against, a mighty step in the advancement of medicine would be taken. The impulse to such progress should come from improved instruction in our medical schools, and in the management of our hospitals. We much need also an unprejudiced and exhaustive history of the progress of biological inquiry since the Middle Ages, with its present result in therapeutics. Such a history may be expected to confirm the not unfounded opinion that the most important advances in practical medicine have been made by methods which are not in any way at variance with our natural instincts of justice and mercy.