I may remind you that each of the gentlemen referred to, serving under the Poor Law, works within a certain small and definite district; that he is therefore peculiarly competent to speak on the state of the population in that district, on their habits and necessities, on their customary condition of health, and on their liability to epidemic disease; and that the total staff of these officers, taken collectively, representing the medical practice of the whole city, can supply exactly that kind of detailed and precise information which is most serviceable to your Officer of Health, in guiding him to those more general and comprehensive conclusions which it is his business to lay before you. These gentlemen are the habitual medical attendants of the poorer classes; day by day, in the unobtrusive beneficence of their calling, they pass from house to house, and from court to court--the constant recipients of complaint, or the constant observers of ground of complaint--amid all that destitute population on whose condition you require to be informed. They are in the constant presence of the pestilences which reign in our worst localities; they are the chief treaters of endemic disease within the City--of that disease which, by its proportion, measures the success of sanitary changes, or indicates their failure; and it has been the professional education of these gentlemen, as it is their business, to trace such effects to their causes. Their reports would be the authenticated statements of experienced medical practitioners, familiarly conversant with their several respective localities. If it were your wish and object, with utter indifference to expense, to organise the best scheme for procuring to yourselves from time to time a succession of accurate and trustworthy reports on the state of health, and condition of dwellings, in the several districts of the City;--if you were willing to engage a large number of non-medical persons who should give their whole time to the duty of exploring and reporting on that state, I am persuaded that this expensive and cumbrous proceeding would have a smaller measure of success than that which I submit to you, and which consists essentially in availing yourselves of the local knowledge and daily observations of a staff of officers, already organised and in active occupation for the very purposes in question.