To give practical effect to their efforts, it was determined in May last to undertake a systematic investigation of the sanitary condition of the city. For this purpose a central organization was formed, and when I mention the names of its leading members, I give you the best assurance that the work was undertaken in the interests of science and humanity. The president was Dr. Joseph M. Smith, one of the ablest writers on sanitary science in this country, and among its members were Drs. Valentine Mott, James Anderson, Willard Parker, Alonzo Clark, Gurdon Buck, James R. Wood, Charles Henschel, Alfred C. Post, Isaac E. Taylor, John W. Draper, R. Ogden Doremus, Henry Goulden, Henry D. Bulkley, and Elisha Harris. In prosecuting this inquiry the Association was guided by the experience of similar organizations in Great Britain, where sanitary science is now cultivated with the greatest zeal, and is yielding the richest fruits. As a preliminary step to the introduction of sanitary reforms, many of the populous towns of England made a more or less complete inspection of the homes of the people to determine their condition, and to enable them to arrive at correct conclusions as to the required remedial measures. The English Government undertook a similar investigation through its “Commissioners for Inquiring into the State of Large Towns and Populous Districts,” and the voluminous and exhaustive reports of that Commission laid the foundation of the admirable sanitary system of that country. The first object of sanitary organization was apparently, therefore, to obtain detailed information as to the existing causes of disease and the mortality of the population, and as to the special incidence of that mortality upon each sex, and each age, on separate places, on various occupations; in fact, to present a detailed account of what may be called, in commercial phrase, our transactions in human life. [Sidenote: A House-to-House Inspection] Evidently the best method of arriving at such knowledge was by a systematic inspection. And that inspection must be a house-to-house visitation, in which the course of inquiry not only developed all the facts relating to the sanitary, but equally to the social condition of the people. It must necessarily be required of the inspector that he visit every house, and every family in the house, and learn by personal examination, inquiry, and observation, every circumstance, external and internal to the domicile, bearing upon the health of the individual.