THE results of the chemical and bacteriological examination of the London waters for the twelve months ended Decembei 31, 1937, are contained in the thirty-second annual report of the Metropolitan Water Board, recently issued (P. S. King and Son, Ltd., 14 Great Smith Street, Westminster. 10a.; 6d.). Much of the report was drafted by the late director, Col. Harold, before his death last, July, and the task of completing it has fallen upon the deputy director, Mr. Denison Byles. The total average output from the works for the year was 310-79 million gallons per day. Of 22,000 routine samples examined bacteriologically, about 98 per cent were of first-class purity (absence of Bact. coli in 100 c.c.). Details are given of several researches carried out in the laboratories. In the Bacteriological Section, various methods for the isolation and identification of Bact. coli have been tested and compared. In the Biological Section, investigations into the algal flora of raw and stored waters have been continued. In the Chemical Section, a further account is given of the use of a new photo-electric turbidimeter. The chief analytical results for each month in the year of the several sources of supply are given in a series of tables.