Putrescible Fluids
Although I do not propose to enter into the details of the plumbing and sewerage arrangements, it is nevertheless necessary to touch upon certain broad questions. Wherever organic refuse is mixed with water putrefaction results, and certain gases are given off from putrefying liquids which are poisonous and hurtful to mankind. Every cook and housemaid is familiar with the fact that all vessels which serve as receptacles for putrescible liquids require the most careful cleansing, and need to be scrubbed and scoured, washed with hot water and soap and soda, and wiped dry. If this is not done they become foul, and rapidly cause the decomposition of any liquid containing organic matter which may be subsequently added.
The modern house drains into a sewer, which is necessarily always foul and filled with the gases of putrefaction. These gases are the result of microbial action. The sewage water is full of microbes, the gases of putrefaction are the gaseous 'toxins' (CO2, H2S, CH4, NH3, &c.) which result from their growth. The air of the sewer is necessarily harmful in itself, and the presence or absence of microbes in the sewer air is a matter of practically small importance. The house drains are necessarily foul as well as the sewers. We hear a great deal about 'self-cleansing' sewers, which shows how ignorant are the surveyors and others who use such terms. A glazed pipe, with a good gradient, may be less foul than a rough sewer with insufficient gradient, but you can no more have a 'self-cleansing' sewer than you can have a self-cleansing saucepan or chamber-vessel.
The foulest place in a house is the kitchen sink, with its vegetable and animal débris, such as cabbage-water, grease, &c. Sanitary engineers are trying to cleanse these places by automatic flushing with cold water, which, to say the least, is enterprising. A few years ago 'fat traps' were fashionable, but were soon found to be intolerable from their inexpressible foulness.
It must be remembered that wherever along a line of drainage you get stagnation there must be putrefaction, and it must be borne in mind that every 'trap' which is a contrivance for ensuring stagnation is necessarily a place where putrefaction is liable to take place. Traps may keep back the smell of the street sewer in house pipes, but it must never be forgotten that they are undesirable evils in themselves.
The efforts of modern sanitary engineers are directed towards ensuring that the gases which inevitably result from putrefaction in sewers and house-drains should be as much as possible diluted with external air before we breathe them. The sewer gratings in the streets give off foul gases at the pavement level, especially in the summer. The ventilating pipes give off foul gases at the roof level, close to the water cisterns. The traps beneath every W.C. and sink are all spots where putrefaction may and often does take place. The gullies in the front and back areas of the house are also liable to be foul. Here I would insist that every gully on the ground level should, when possible, be freely exposed to the air, so that the wind may blow over it. This, in London, is impossible, as these gullies are necessarily surrounded by the walls of the area, and in still, muggy weather these areas must contain a large amount of gaseous toxins.
I insist upon this point because I see the town architect making the mistake in the country of enclosing the kitchen and pantry gullies by walls (to form a kitchen yard), so that any emanations which arise from them are liable to be drawn into the house through the open windows. Such an arrangement ought, when possible, to be carefully avoided.
Traps and trapped gullies are evils which are only to be tolerated for the prevention of greater evils. I visited not long ago a convalescent home built on the slopes of a decidedly steep hill. The building was a fine one, and (why I do not know) was three storeys high. The builder had brought the rain-water pipes from the roof, and had made them terminate in trapped gullies close to the front wall of the house. In these collections of stagnant water, dead leaves, &c., would certainly decay, and every trap would inevitably become a cultivating chamber for the growth of mildew and moulds of various kinds. These trapped gullies communicated with an underground drain, where the same growth of mildew, &c., would inevitably go forward. In such a situation the rain-water, without the interference of the builder and architect, would have got clean away into the valley below, and have left the house perfectly dry. All that was needed was an open gutter. Great expense had been incurred to make the walls of this building dry, and still greater expense had been incurred to ensure precisely those evils which come from damp walls, viz., the growth of mildew.
In the autumn of 1896 I was stopping in an hotel which had no less than 42 trapped gullies touching its walls; there was one beneath almost every window and by the side of almost every door. Here, again, a little contrivance and common sense would have obviated all this mischievous expense.
The constant inhalation of the gases of putrefaction is a great danger to health, otherwise sanitarians would not lead us to imply that we ought to spend enormous sums to ensure their dilution before we inhale them. If these gases be concentrated, they are capable of killing strong men in a few minutes. The constant inhalation of these gases in a more diluted form leads to malnutrition, and one must suppose that the pasty-faced and undersized Cockney is made in this way. We have little certain knowledge of the diseases caused by sewer air. Personally, I should say that anæmia and malnutrition are the chief resulting evils, and that these conditions make us very vulnerable to infections. Sore-throat is certainly a drain disease, and thus a vulnerability to diphtheria is probably engendered. Puerperal disease of various kinds and rheumatic fever are among the diseases which have been attributed to sewer air, and it is probable that chronic enlargement of the tonsils and the surprising increase of adenoid growths in the pharynx and naso-pharynx are not without similar relationships.
Dr. Letheby and Dr. Haldane, who both investigated cases of acute poisoning by air in sewers, came to the conclusion that sulphuretted hydrogen was the fatal ingredient.
Dr. Haldane is of opinion that the source of the sulphuretted hydrogen is the kitchen refuse in the fat traps and grease boxes. He states that ·07 per cent. (or a mixture containing 7 parts of sulphuretted hydrogen with 9,993 parts of air) is poisonous.
It is probable that the constant inhalation of very small quantities indeed would be prejudicial to health.