According to the method adopted in my [last Annual Report], I now proceed to offer you such observations as another year’s experience may justify, on those physical influences which prevail against life within the City of London, and on such remedial measures as seem aptest to remove them.
Sub-soil Drainage, House-Drainage, and Sewerage.
1. In respect of drainage, I have already adverted to those unwholesome conditions which prevail along the low-lying valley of the ancient Fleet, and have mentioned to you that frequent incursions of the river aggravate whatever mischief is inherent in the soil, by maintaining it as a perpetual swamp, and by favoring in it a constant succession of putrefactive changes. I have likewise illustrated to you the probability that, in some of the higher portions of the City, chiefly in the Out-Wards of Cripplegate and Bishopsgate, there still survive some properties of that old malarious fen, from which these districts were originally reclaimed. Stow seems in his day to have had misgivings on this subject; for after describing the improvements that had been effected there, and the gradual levelling and heightening of the ground, he adds, ‘it seemeth to me that if it be made level with the battlements of the city wall, yet will it be little the dryer, such was then the moorish nature of that ground.’
From a consideration of this former geography of the place, and from observation of the diseases which prevail there, I am led to think it highly probable, that some of its sanitary defects depend less on defective house-drainage than on a still marshy undrained condition of the ground itself, and that these defects would be removed by an efficient application of sub-soil drainage.
I would therefore respectfully recommend to you, under this head, that the state of soil in the specified districts be referred to competent authorities, and that such measures be adopted as inquiry may prove requisite, for relieving those parts where the sub-soil drainage is imperfect, and for protecting the house-foundations, and sewers, and sub-soil adjacent to the river, from being soaked or flooded by the tide.
2. With respect to house-drainage, I have no addition to offer to those remarks which I submitted to you in my [last Report]. Your Hon. Court has fully recognised that immense peril to life which is connected with the presence of cesspools beneath houses, and which depends on their poisonous emanations. At the commencement of the present year, your Surveyor stated that he might take ‘5414, as a fair approximation of the number of cesspools’ then in existence within the square mile of the City of London. This proportion, dangerously large as without doubt it is, presented an important diminution from the number which existed a year previously, when your Commission first obtained from the Legislature authority to enforce their closure; and it may reasonably be anticipated that at the termination of this present year, a still further abatement will be recorded in the magnitude of that destructive nuisance.
3. Notwithstanding the variety of stink-traps to which you have given trial, and notwithstanding the fact (recorded by your Committee of Health on the Surveyor’s authority) that ‘there does not exist within your jurisdiction a single gully which is untrapped,’ there continue to be frequent complaints of offensive exhalations from the sewers.
The mechanical difficulties in this matter of trapping have appeared to be, from the nature of the case, almost insuperable. It may, indeed, easily be conceived, how incompatible are the common uses of a gully-hole with such fineness of adjustment and delicacy of balance as would render the apparatus air-tight from within, and effectually preclude an escape of the gaseous contents of a sewer. Under such circumstances, your Hon. Court has desired that I should express my opinion, how far a different course might be adopted in respect of these exhalations; how far, namely, they might be neutralised within the sewers; how far it might be chemically feasible, and in a sanitary point of view expedient, that a systematic use should be made of deodorising agents; so that any gas escaping from the sewers should at least be divested of its original smell.
On this subject, I would submit to you the following considerations. As respects its feasibility (putting aside as foreign to my province all questions of the expense, and all details of the daily arrangement) a first and obvious objection is this: Granted in the abstract, that sewer-gases can be converted by appropriate agents into inodorous compounds; in the practical application of these agents, you would find impediments with which you are already familiar. Theoretically, there may be no difficulty in providing air-tight traps; practically there is said to be every difficulty. Just as that mechanical problem has defeated you in practice, so would the chemical one; and for the same reason. The fulfilment of either problem is a matter of nice adjustment. In proportion as your gully-hole is exquisitely trapped, it becomes liable to obstruction; it loses its use as an inlet to the sewer, nearly in the same measure as it becomes an effective obstacle to regurgitant gases. Similarly, in proportion as these alleged deodorisers might succeed in completely stifling the characteristic odour of sewage, they would be liable to diffuse perfumes peculiarly their own, and to establish, in the vicinity of gully-holes, the alternation of a new nuisance with the old. To proportion with accuracy the introduction of these chlorinous preparations to the amount of refuse traversing the sewers—an amount varying most considerably at different hours of the day, seems to me quite a visionary hope. Failing such accurate proportions, I am not prepared to say that the result would be useful; and I accordingly consider the scheme as not chemically feasible.
Further—as involving an important sanitary principle, I would say, that the great object which must be aimed at is not the mere chemical neutralisation of certain stinks which arise within your jurisdiction, but the closest possible limitation, and the promptest possible removal of all those materials which are decomposed into fœtid products. Admirable, no doubt, is that arrangement by which Nature, stationing a sense of smell at the inlet of our breath, cautions us by this vigilant sentinel against the inhalation of many poisonous airs; but, in respect of organic decomposition, I am in no degree satisfied that its odorous products are its only, if even its principal, agents of injury; nor have I any reason to suppose that the real detriment to health which arises from breathing the miasms of sewers or marshes, of cesspools, burial-grounds, or slaughter-houses, would in any important degree be lessened by the mere mitigation of fœtor in their effluvia. Offensive as these are, they at least answer the useful purpose of warning us against the other poisons with which they are associated.