"The principal cause of the extent of zymotic disease," wrote the Medical Officer of Health for Mile-End-Old-Town, in 1859, "is the defective state of the habitations of the poorer classes. The remedy for the evil is only to be secured by a systematic house visitation. "... Without a general house inspection it is impossible to secure the proper entry to and use of the expensive sewers which have been and are being constructed. "Having done so much for the streets, pavements, and drains, the improvements will lose half their salutary effect if the interior of the dwellings are not placed in a corresponding condition of wholesome cleanliness." "It is," wrote the Medical Officer of Health for Whitechapel, "to the interior of the houses that our attention must be directed, for it is here that the source of disease is usually found.... An habitual and detailed inspection of the houses occupied by the poorer classes is therefore essential." A house-to-house visitation was, indeed, the first essential. By no other means could the actual condition of the abodes of the people be ascertained, and the breeding places of disease be discovered, cleared out, and rendered innocuous. And as there was a never ceasing tendency on the part of the poorer classes to sink into a condition of uncleanliness, and on the part of their abodes to fall into dilapidation, or, as it was expressed, "a pertinacity for dirt," so was constant inspection and supervision of vital necessity for the maintenance of any improvements made. "There are," wrote the Medical Officer of Health for St. Pancras (1858), "many parts of the parish densely crowded. Some of the people have become so used to filth, they appear to prefer it to cleanliness; at any rate, they have not the energy to get rid of it and improve their condition. Such houses--perfect hotbeds of infectious diseases--ought to be visited two or three times a year...." The Medical Officers of Health had one valuable object lesson before them in the common lodging-houses, which, regulated and inspected by the police under the Acts passed by Parliament, had shown that even the very worst conditions of life could be ameliorated, and that the very lowest and most miserable classes of society were not beyond improvement. "The chief points which are regulated by the authorities (the Police) are cleanliness, drainage and water supply, the separation of the sexes, and the prevention of overcrowding. The testimony of all who are acquainted with the dwellings of the poor is concurrent as to the immense sanitary advantages gained by the provisions of the Common Lodging Houses Act, and the results had been to improve in a marked degree the health, habits, and morals of the persons using these places."[75] "The cleanliness, comfort, and ventilation of the licensed rooms in common lodging-houses offer a very marked contrast to those which are unlicensed."[76]