Figs. 29 and 30 are intended to show the plan and section of a group of the smallest town tenements, with a scavenger's alley between them and the three gutters, two closed at both ends, to be filled with absorbent material to collect the urine, and one to be filled with non-absorbent material to filter and aërate the slop-water, which should always flow in open channels when practicable. The 'scavenger's alley' should be protected by gates. It is thought that the excrement would be primarily collected in comparatively small vessels, like garden water-tanks upon wheels. The excrement having been allowed to drain before collection, and being in a semi-dry, sticky condition, would have no tendency to slop about during a journey, and in a covered vessel such as I have described might be sent any distance without danger or offence. Arrived at the farm the tank would be transferred to a second pair of wheels, and by being tilted would easily deposit its contents in a furrow previously made in the ground with a spade. The tank should be dried and lime-whitened and returned to the town, and three days after the deposit of the excrement in the ground, plants of the cabbage order should be dibbled in. Cabbages and their allies are the only plants which really flourish in the fresh material; but after the cabbage crop has been harvested any garden crop may be grown, and it will be found that the fertility of ground treated as I have suggested is very great and very persistent. The best method of treating kitchen waste and putrescible refuse, such as cabbage leaves and the trimmings of vegetables, &c., is to throw all together into a heap enclosed by a circle of wire netting. In the course of a few months complete humification will take place. CHAPTER IV OVERCROWDING, ITS CAUSES AND EFFECTS I have been at some pains to demonstrate the dangers and inconveniences which are inseparable from houses built, as are the majority of town houses, upon an area which is wholly insufficient when considered in relation to their cubic contents. Feeling, as I do, that the question of space round the dwelling is of the greatest importance—so important that every other sanitary regulation sinks into insignificance when compared with it—I have endeavoured to show how detached houses may, to their great advantage, be independent of the public sewers, and equally independent, if their owner choose, of public water supplies; and this I have done in the hope that in country places, and places which are developing, the precious boon of living in a detached house may be recognised. While I am not slow to admit that water under pressure is a great advantage if it be wisely used, I have pointed out persistently for some years that our present system of water-carried sewage gives a 'fatal facility' to the overcrowding of houses, and has made life, of a sort, physically possible under conditions of overcrowding which have never been equalled in the history of the world.