The Metropolitan Commissioners of Sewers were duly appointed, and they divided the area over which they had jurisdiction into seven separate sub-districts, with a Commission for each. The creation of this body constitutes a great landmark in the sanitary evolution of London, for it was the first recognition by Parliament of the great principle of the unity of London; of the necessity--at least so far as regarded one matter--for one central governing authority for the numerous populations, and bodies, and districts which were becoming welded together into one mighty town and one vast community. It is true, the recognition extended only to this one matter, and that the Central Board was to be a Board nominated by the Crown, and without any vestige of representation upon it, but none the less it was a forward step towards a sounder and wiser system of government than that which had hitherto prevailed. That the new body failed to prove equal to the task imposed upon it was due as well to the constituent members thereof as to the imperfections of the machinery devised by the Act. Its failure, however, in no way controverted the soundness of the great principle thus, for the first time, recognised by Parliament. The evidence given before the Royal Commissioners brought into view the enormous area of filth and limitless insanitation in London: it displayed some of the principal sources of the excessive amount of disease and premature mortality; and to some extent it elucidated the principles and demonstrated the practicability of large measures of prevention. And it also disclosed the regrettable fact that since the epidemic of cholera in 1832 there had been little or no improvement in the sanitary condition of many parts of the metropolis--indeed, in most parts of it the evils were wider spread and acuter in form, whilst, owing to the increase of population, the numbers affected were vastly larger.