The rules which regulate the laying of land-drains apply with equal force in the making of sewers, that is no part of the pipe should be less perfect, either in material[pg 232] or construction, than that which lies above it; and where the inclination becomes less, in approaching the outlet, silt-basins should be employed, unless the decreased fall is still rapid. The essential point of difference is, that while land drains may be of porous material, and should have open joints for the admission of water, sewer pipes should be of impervious glazed earthen-ware, and their joints should be securely cemented, to prevent the escape of the sewage, which it is their province to remove, not to distribute. Drains from houses, which need not be more than 3 or 4 inches in diameter, should be of the same material, and should discharge with considerable inclination into the pipes, being connected with a curving branch, directing the fluid towards the outlet.

In laying a sewer, it is customary to insert a pipe with a branch opposite each house, or probable site of a house.

It is important that, in towns not supplied with waterworks, measures be taken to prevent the admission of too much solid matter in the drainage of houses. Water being the motive power for the removal of the solid parts of the sewage, unless there be a public supply which can be turned on at pleasure, no house should deliver more solid matter than can be carried away by its refuse waters.

The drainage of houses is one of the chief objects of sewerage.

In addition to the cases cited above of the model lodging houses in Lambeth Square, and of the buildings at Westminster, it may be well to refer to a remarkable epidemic which broke out in the Maplewood Young Ladies' Institute in Pittsfield, Mass., in 1864, which was of so violent and fatal a character as to elicit a special examination by a committee of physicians. The family consisted, (pupils, servants, and all,) of one hundred and twelve persons. Of these, fifty-one were attacked with well-defined typhoid fever during a period of less than three weeks. Of this[pg 233] number thirteen died. The following is extracted from the report of the committee:

"Of the 74 resident pupils heard from, 66 are reported as having had illness of some kind at the close of the school or soon after. This is a proportion of 33/37 or nearly 90 per cent. Of the same 74, fifty-one had typhoid fever, or a proportion of nearly 69 per cent. If all the people in the town, say 8000, had been affected in an equal proportion, more than 7000 would have been ill during these few weeks, and about 5500 of them would have had typhoid fever, and of these over 1375 would have died. If it would be a more just comparison to take the whole family at Maplewood into the account, estimating the number at 112, fifty-six had typhoid fever, or 50 per cent., and of these fifty-six, sixteen died, or over 28.5 per cent. These proportions applied to the whole population of 8000, would give 4000 of typhoid fever in the same time; and of these 1140 would have died. According to the testimony of the practising physicians of Pittsfield, the number of cases of typhoid fever, during this period, aside from those affected by the influences at Maplewood, was small, some physicians not having had any, others had two or three." These cases amounted to but eight, none of which terminated fatally.

The whole secret of this case was proven to have been the retention of the ordure and waste matter from the kitchens and dormitories in privies and vaults, underneath or immediately adjoining the buildings, the odor from these having been offensively perceptible, and under certain atmospheric conditions, having pervaded the whole house.

The committee say "it would be impossible to bring this report within reasonable limits, were we to discuss the various questions connected with the origin and propagation of typhoid fever, although various theoretical views are held as to whether the poison producing the disease[pg 234] is generated in the bodies of the sick, and communicated from them to the well, or whether it is generated in sources exterior to the bodies of fever patients, yet all authorities maintain that a peculiar poison is concerned in its production.

"Those who hold to the doctrine of contagion admit that, to give such contagion efficacy in the production of wide spread results, filth or decaying organic matter is essential; while those who sustain the theory of non-contagion—the production of the poison from sources without the bodies of the sick—contend that it has its entire origin in such filth—in decomposing matter, especially in fermenting sewage, and decaying human excreta.

"The injurious influence of decomposing azotised matter, in either predisposing to or exciting severe disease, and particularly typhoid fever, is universally admitted among high medical authorities."