But is there no danger in using organic refuse, which may be infective and dangerous, as an application to the land? To this I should say emphatically 'No,' provided it be put in the upper layers of the soil, and the soil be tilled. Our organic refuse, when allowed to putrefy in water, and to trickle _under pressure_ to our wells, or run direct into our sources of drinking-water, has turned millions of pounds into the pockets of members of my profession, but when rationally used as a top-dressing for the well-tilled soil it has never, that I am aware of, produced any harm. I have tried to investigate this matter. Some five years ago I constructed a well five feet deep in the middle of a garden which is plentifully manured with all that is most loathsome to our senses. This well is lined to the very bottom with concrete pipes, further protected by an external coating of concrete; the junctions of the pipes are securely closed by cement, and there is a good parapet and efficient cover (see page 65 and figs. 22 and 23). Now no water can possibly enter the well, except through the bottom. The water in it is clear and bright, and since its construction no mud has collected on the bottom. The sides of the pipes also remain absolutely clean, so much so that when, in 1895, I showed this well to a party of scientific friends, some of them dropped a hint that it had possibly been scrubbed in honour of their visit. This, however, was not the case. The water from this well has been examined three times chemically, with the result that it has been pronounced free from organic impurities, and three bacteriological examinations have been made, with the result of showing a bacterial purity which is quite exceptional. The last examination was made by Dr. Cartwright Wood in November 1895, and showed a very high degree of bacterial purity. The water was specially examined by Dr. Wood for the presence of _Bacterium Coli commune_, but with negative results. Dr. Wood writes: 'The results are exceedingly satisfactory, and I must admit surprised me very much.' A surface-well on this pattern has lately been constructed in a village near Andover, and the results, as far as the appearance of the well and water is concerned, seem to be entirely satisfactory. When people live crowded together in cities, the difficulties connected with the cleaning of the houses are very great. After the invention of the steam-engine it was found possible to supply even the top floors of the highest houses with an ample supply of water. We accordingly abolished the scavenger, and adopted a complete system of water-carried sewage. In this way our houses have been cleansed, and our rivers and surface-wells have been fouled, and it is difficult to say whether at present there be a balance of advantage or disadvantage. We have had epidemics of cholera and of typhoid, and it is almost certain that there is no one here present but has suffered in some way or other from the 'drains.'