FIG. II.-CURVES SHOWING THE PARALLELISM BETWEEN THE PERCENTAGE 
OF SPECIMENS SHOWING THE COLON BACILLUS AND THE QUANTITIES 
OF NITRITES IN THE SEVERAL RESERVOIRS. 
BULLETIN 35, HYGIENIC LABORATORY. P. H. & M. H. S. 
__ NITROGEN AS NITRITES IN PARTS PER MILLION X 10,000 
THE NCRHIS PETERS CO-. WASHINGTON .■ O. C- 
