In the following year it again appeared in more severe epidemic form over the whole of the metropolis. On one day--September 4th--there were 459 deaths from it. The climax was reached in the second week in September (almost the identical date on which the epidemic of 1849 occasioned the highest mortality) and there were 2,050 deaths from it.[50] In that one month 6,160 persons died from it, and from July 1st to December 16th, when it at last disappeared, there was a total mortality from cholera alone of 10,675 persons. Every conclusion which had been arrived at as regards the disease during the previous epidemics was confirmed by this third great epidemic, and many previous theories passed into the region of proved facts. Cholera was once more proved to be a filth disease, and in the main confined to filthy localities. The more defective and abominable the methods of drainage, the larger the number of victims. The filthier and more contaminated the water supplied for drinking and household purposes, the more numerous the cases, and the more virulent the disease. This was demonstrated beyond further question. The mortality on the south side of the Thames was above threefold what it was on the north side; and both as regarded water supply and drainage, South London was in a worse sanitary state than North London. The water consumed by the population there was generally worse than that on the north. Lying lower, too, the drainage had less chance of being conveyed away, and in the miles upon miles of open sewer ditches it was left to rot and putrefy in close propinquity to the houses and to poison the air. And the most remarkable proof was afforded by the effects of the consumption of water taken from different sources. In 1849 both the Lambeth and the Southwark Water Companies pumped the water they supplied to their customers from the very foulest part of the Thames--near Hungerford Bridge--with equally disastrous results. In the course of the following years the Lambeth Company removed its source of supply to a part of the river above Teddington Lock--the Southwark Company, however, went on as before. In the epidemic of 1854 the inhabitants of houses supplied with the water by the latter company suffered eight times as much as those supplied by the better water of the Lambeth Company, whilst the number of persons who died in the houses where the impure was drunk was three and a half times greater than that in the houses where the purer water was supplied. Of all the conclusions arrived at by those who had been engaged in combating the disease during this epidemic, the most important was that where cholera had become localised it was connected with obvious removable causes, and was in fact a preventable disease. Most unfortunately, and reprehensibly, many of those who could have done most to prevent it failed signally to take action.