=Relative Merits of Dry and Wet Methods.= No absolute answer can be given in exclusive favour of either plan. Each is the best under different circumstances; the dry method being chiefly suitable for small villages, and for temporary collections of people, as in camps; and the wet method for towns. The question of value of manure does not enter into the problem, as it seldom repays for carriage. The =objections to the water-carriage system= are really due to its not being carried out in an efficient manner. When sewers are properly laid; when they, as well as house-drains, are freely ventilated; when house-drains are efficiently trapped and ventilated near their junction with the sewer; when the drains are efficiently flushed, and the outflow from the sewer is unimpeded, the objections disappear. These objections are that—(1) the sewers, as underground channels, transfer effluvia and the germs of disease from one place to another; (2) pipes become disjointed owing to being badly laid, and the ground is contaminated; (3) the water supply is in danger of receiving impurities from the sewers. These objections do not hold good in practice. The contamination of water-mains or of wells from sewers implies gross carelessness in the method of laying of sewers or pipes. The only objections which are of any force, are (4) that water-closets require a large amount of water, and the sewage obtained is greatly diluted, and consequently diminished in value; while (5) the disposal of such an amount of water, in the case of a large inland town, is a problem of the utmost difficulty. Modern engineering enterprise by bringing water from a greater distance, and by aiding the discharge of sewage when necessary by pumping, has overcome these difficulties. There are many =objections to the dry methods= of removing excreta. (1) Whatever dry method be adopted, the excreta are retained for some time in or about the house, instead of being immediately removed. (2) Although the initial outlay in closets and sewers is less than with the water-carriage system, there is the constantly recurring expense of removing the excreta, as well as of cleansing the pails, etc. (3) In the dry-earth closets, the provision of dry earth or other material involves some expense. (4) Whatever dry method be adopted, sewers are always required to carry off the foul water, as well as liquid trade products, and a certain proportion at least of the urine. It is impossible to supply sufficient dry earth to absorb all the urine and slops of the population. Thus, as the Indian Army Sanitary Commission said, speaking of barracks, “to have two systems of cleansing stations—a foul-water system, and a dry-earth system—would simply be paying double where one payment would answer; or, if all the excreta, solid and liquid, are to be carried away, this must be done at a cost ten times greater than that which would be necessary, if all the excreta were removed by drains.”