"Whilst the houses' drain-pipes, from defective construction and workmanship, and want of being cut off from the main sewer, act as much as sewer ventilators as channels for removing filth ... whilst overcrowded houses and foul smells in living and sleeping rooms are taken as a matter of course; whilst infectious disease is sedulously propagated first by concealment, and then by criminal exposure and neglect, ... so long the yearly recurring Herodean massacre of helpless children, whose almost sole use in life appears to be the providing of fees for doctors and undertakers, will continue, in spite of all efforts of sanitary authorities and sanitarians." The evil done, however, by bad sanitary conditions was not limited to the children who died. Probably ten or twenty times the number of those who died went through the illness and survived--but of those many were injured in constitution for life. In other respects, however, sanitary progress was being made, and slowly but steadily the conditions of the health of the public were improving. Undoubtedly the main causes of that progress were the great system of main drainage and sewerage which had relieved London of the incubus of enormous accumulations of the deadliest filth in its houses, and of an open main sewer through its midst; and the greater quantity, and improved quality, of the water supplied for household consumption which relieved her inhabitants from the necessity of drinking liquid sewage. And the construction of sewers in nearly all the streets, and the substitution of an effective system of house drainage instead of the abomination of cesspools, was also a great stride to improvement. Since 1856 plans for the construction of a total length of nearly 1,000 miles of local sewers had been submitted to the Metropolitan Board for their approval, many of them being in substitution of old and shallow ones for which the Board's new main and intercepting lines afforded the means of improving the gradient and outlet. In their report for 1881 the Metropolitan Board of Works gave "a brief summary" of what it, as the Central Authority, had accomplished since 1856. "There was the great main drainage work which had cost about five and three-quarter millions, an undertaking which 'although fruitful of good results, and of greater magnitude than anything of a similar kind that had previously been accomplished, has left, as might be expected, few visible marks of its existence.'" It is rather the Thames embankments and broad new streets which remind the inhabitants of London of the great changes and improvements that the Board's operations effected.