Part 15

II. THE CAUSES AND THE PREVENTION OF ENDEMIC DISEASE.

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.

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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.

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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.

Let me likewise take the opportunity of correcting a misapprehension, which, by the use of an inappropriate word, is sometimes shown to exist on this subject. The agents in question are spoken of as dis-infectant. As there is no scientific reason whatever for believing that they in any degree interfere with the spread of epidemic or infectious disease, and as an erroneous opinion on this point may lead to the neglect of measures which are truly precautionary and useful, I think it well to state explicitly, for your information, that I have no evidence of their possessing any other utility, in the respects under consideration, than simply and singly that of removing stink from the atmosphere around them.

For reducing to a minimum the exhalations which arise from sewers and house-drains, it appears to me that the following are the essential principles: First, to render the current through them as rapid as possible; and, above all, by every care for their form, their junctions, their slope, and their material, to provide against the occurrence of obstructions and deposit: Secondly, to employ in their construction, so far as may be possible, such substances as are porous in the least procurable degree; such as consequently will be least apt to imbibe and retain in their interstices any considerable impregnation from the fœtid fluids running over them at intervals; such, too, as will be least likely to permit soakage into the surrounding soil: Thirdly, by reducing the size of drains and sewers to the lowest dimensions compatible with a full performance of their uses, to diminish to the utmost the extent of their interior evaporating surface, and of those large chambers which they now offer for the evolution, retention, and diffusion of gases.

To the application of these principles (together with a sufficient and appropriate distribution of water) far more than to chemical agents, or to the invention of mechanical traps, I believe that you must look for rendering inodorous the vicinity of your numerous gully-holes. I content myself with stating them to you, as a practical deduction from physical laws, without venturing to offer any opinion on the degree in which they are applicable within your jurisdiction, or on the manner in which they should be applied. For although, as principles, they have their foundation in physics, and although their importance to sanitary improvement is beyond measure great, all details relating to their application lie out of my province, and belong to a class of subjects in which your Surveyor’s opinion will, of course, be infinitely more useful to you than mine.

Water-Supply.

During the past year, as in the preceding one, I have given frequent consideration to the subject of water-supply within the City.

I have already endeavoured to convey to you the deep sense which I entertain of its importance, and I have every reason to believe that your Hon. Court recognises, at its full weight, the necessity of providing for the City of London a supply of water which in quantity shall be ample, in quality pure, in distribution constant and accessible.

In my former Annual Report, and in some remarks subsequently addressed to your Committee of Health, I dwelt especially on such defects of our present system as relate to the quantity and distribution of water; endeavouring to illustrate the insufficiency of its supply to the poorer tenements of the City, and the extreme inconvenience which is entailed on their inmates, sometimes by dependence on a common tap, sometimes by the troublesome, expensive, and unwholesome necessity of storing water.

In reverting to this subject, I may correct a fallacy which is apt to prevail with respect to the abundance of supply. I have no reason whatever to doubt that a very liberal allowance of water is daily pumped into the City--enough, or more than enough, so far as I know, to fulfil all necessary purposes.

But those purposes are not fulfilled by it. A certain large figure is stated as representing the average quantity daily driven through the mains of the City; this quantity is divided by the number of residents within your area, and the inference is drawn that each individual inmate of the City has at his disposal 25 gallons a day; or (after deduction for public purposes and the like) 21¼ for his domestic supply. As an arithmetical conclusion from the premises this may be true: nothing can be less accurate as a practical representation of the facts. An average amount of three million gallons per diem may, or may not, be pumped through the mains of the City: but to calculate the available water-supply from this dividend, without previous deduction for the immense escape of un-available water by waste-pipes or otherwise, gives a most fictitious result. The large waste which naturally arises in the system of intermittent supply has been well illustrated by some evidence given by Mr. Lovick before the late Metropolitan Commission of Sewers, in respect of a particular block of nearly 1200 houses. Some of the houses were of the higher, and many of the poorer class, but the average might be stated to be of the middle class, and to present a fair example of an urban population. The drainage of all these houses was discharged through one main sewer. The run of water through this sewer was carefully watched and gauged every hour, during the night as well as the day, on days when the water was on, that is to say, when the intermittent supplies were delivered, and also on the ordinary days, when the consumption of the houses was from butts and cisterns, into which the intermittent supplies were delivered. The gaugings of the discharge of waste water into the sewer were checked by gaugings of the consumption of water from the butts and cisterns, during the interval of the delivery of the supply by the company. It was ascertained that the average quantity discharged per diem through the sewers was 44½ gallons per house; but it appeared that, on the days when the intermittent supplies of water were on, the quantity discharged per diem was 209 gallons per house. The waste in this district from defects in house apparatus of distribution, incident to an intermittent supply of water, was, on the water days, three and three quarter times greater than the consumption on those days.

General Board of Health Report on Supply of Water to the Metropolis, page 120.

No similar gaugings have, I believe, been made within the City; so I am unable to tell you with accuracy what are the proportions of waste and consumption. In an interview with your Committee on Health, when they were collecting information on the subject, Mr. Mylne, the engineer of the New River Company, stated (as a reason against fulfilling some object desired by the Committee) that within the City of London, in connexion with its distributing apparatus, there existed for the escape and waste of water, during the period of supply, ‘at least 10,000 open cocks.’

Assuming the accuracy of this statement, I doubt whether the average available supply of water for domestic purposes within the City can possibly exceed a quarter of its alleged quantity; and I am persuaded that there must be large numbers of persons to whom the enjoyment even of that reduced average is utterly unknown. Your Hon. Court, observing the incalculable waste, and knowing that the cost of water-supply (as of all other commodities) must of necessity vary according to the quantity supplied, can appreciate the consequences of so much fruitless expenditure.

I would beg likewise to observe to you that this unapplied flood of water is in itself not unobjectionable. It would be of questionable advantage if the drainage of the City were so perfect as to carry all away without inundation of the soil; while under opposite circumstances, in every quarter where drainage is absent or faulty, evil must arise from the extensive and habitual infiltration of moisture.

On the extreme inconvenience which attends the storage of water in the poorer habitations of the City, I have already reported to you, and will now only add that increased experience has given much confirmation to my view. Their receptacles are generally such as contribute to the contamination of water, and are constantly so arranged as to invite an admixture of the most varied impurities.

In the large proportion of them, which are open casks, one sees habitually a film of soot floating on the surface; one sees (if indeed one can see so deeply into water which is often turbid and opaque) that filth and rubbish lie at the bottom; one sees the interior of the cask itself dirty and mouldering.