SEWAGE OUTFALLS AND DISCHARGE 329 



accomplished by washing with weak chlorine or acids. 

 Obviously, the vendor is not thereby absolved from his 

 attention to the quality of his goods, nor the local authority 

 from the duty of obviating pollution where it is dangerous. 

 We must remember that most articles of the kind we are 

 discussing are habitually washed at least twice, by the retailer 

 and by the private purchaser, before consumption, and that 

 sterilization of dangerous organisms at the same time would 

 scarcely add appreciably to the trouble or cost. 



The danger that has been so much urged of admitting 

 effluents to drinking-water streams, and a great deal of the 

 expense of sterilizing effluents and water-supplies, would be 

 minimized if the consumer also sterilized the small quantity of 

 water used for drinking (estimated at about a gallon per head 

 per day) in a way that 1 have for some years advocated.^ 



During the passage to houses through pipes there is a 

 constant risk of contamination from the liability of the pipes, 

 even under pressure, to suck in polluting matter from the soil, 

 so that it has been frequently demonstrated that the supply to 

 houses is often much inferior to the filtered waters in the 

 reservoirs and mains. Here again a final line of defence is 

 necessary. I pointed out that as sterilization, so far as concerns 

 dangerous organisms, is essential for safety, much of the expense 

 might be saved by making the treatment at the works less costly, 

 since it was superfluous to purify water required for a large 

 number of domestic uses, for flushing the streets, or for sanitary 

 purposes. It became a question whether we should aim at the 

 whole public supply being purified up to the maximum standard 

 of a good drinking-water, with a great extension of stringency 

 as regards discharging effluents, or whether we should be content 

 with a somewhat less purified water for the general supply, and 

 sterilize separately in each house, under some conditions of 

 municipal control, such portions as should be required for food 

 purposes. Of the three methods I have described for rendering 

 the fluid germ-free, the chemical one, by ozone or chlorine for 

 instance, could be employed at the works, while the heat- 

 sterilizer, or Pasteur filter, could be put into the consumer's 

 house by the municipality or by a water company — preferably 

 by the former — as an integral part of the ordinary water fittings, 

 and the duty of keeping it cleansed and in order secured by 

 offlcial inspection. 



^ Cantor Lectures, Journ. Soc. of Arts, Aug. i, igo2, p. 749; also Joiirn. R. San. 

 Inst., vol. xxii., part iv., p. 565. 



