The more imperative is it, therefore, that every effort should be made to raise the health of our people to the highest attainable level, and to maintain it at the loftiest possible standard. The subject is so vast and complicated that it is impossible, within reasonable limits, to treat more than a portion of it at a time. London, the great metropolis, the capital of the Empire itself, constitutes, by the number of its inhabitants, so large a portion of the United Kingdom, that the health of its people is a very material factor in that of the kingdom. It has a population greater than either Scotland or Ireland, greater than any of our Colonies, except Canada and Australasia, greater than that of many foreign States--"the greatest aggregate of human beings that has ever existed in the history of the world in the same area of space." And, in a measure too, it is typical of other of our great cities. A narrative of the sanitary history and conditions of life of the people of London, therefore, would be a material contribution to the consideration of the general subject in its national aspect, whilst it cannot but be of special interest to those more immediately concerned in the amelioration of the existing condition of the masses of the people of the great capital. Such a narrative is attempted in the following pages. It is, in the main, based upon the experiences, and inferences, and conclusions, of men who, more than any others, were in a position closely to observe the circumstances in which the people lived, their sanitary condition, and the causes leading thereto and influencing the same. It includes the principal measures from time to time passed by the Legislature to create local governing authorities in sanitary matters--the various measures designed and enacted to improve the condition of the people--and the administration of those measures by the local authorities charged with their administration. It is a narrative, in fact, of the sanitary--and, therefore, to a great extent of the social--evolution of this great city. It is doubtful how long a time would have elapsed before the condition of the people came into real prominence had it not been for the oft-recurring invasions of the country by epidemic disease of the most dreaded and fatal forms. Ever-present diseases, disastrous and devastating though they were, did not strike the imagination or appeal to the fears of the public as did the sudden onslaught of an awe-inspiring disease such as cholera. An epidemic of that dreaded disease swept over London in 1832, and there were over 10,000 cases and nearly 5,000 deaths in the districts then considered as metropolitan--the population of those districts being close upon 1,500,000.