40 



Marshall O. Leighton 



infusion of leaves (A) except color. There is nothing in the analyses 

 presented, except the unimportant excess of nitrates, that does 

 not surpass on the acceptable side the strictest of the interpretation 

 standards above quoted. The samples were collected almost simul- 

 taneously on September 22, 1904, from Lake Champlain, within 

 the inclosed area lying between the docks at Burlington, Vt., and 

 the harbor breakwater. Sample No. 2 was taken about 1,000 feet 

 away from the outlet of the main trunk sewer of the city. The remain- 

 der were taken at points less than 500 feet away fom said outlet. 

 No. 5 being collected about 20 feet from the sewer's mouth. 

 Ten years previous to the collection of these samples the city of 

 Burlington was obliged to abandon a water intake situated at a much 

 more favorable point than those at which any of the above samples 

 were taken. The reason for the change was the high rate of intes- 

 tinal disease morbidity in the city, which was markedly decreased 

 afterw^ard. What, then, shall we say of sanitary analysis as an 

 index of pollution at Burlington ? Bacteriological examination reveal- 

 ed the abundant presence of B. coli in all the samples reported in 

 Series "B," and the discharge of sewage into the lake was a matter 

 of casual observation. Therefore no one was deceived by the nitro- 

 gen determinations. One may very properly question whether 

 sanitary analyses may not be, under less fortunate circumstances, 

 an actual danger to public health. 

 Let us now examine series "C." 



SERIES "C." 

 Parts per Million. 



Records of color and odor are unfortunately absent, but from 

 independent sources comes the assurance that none of the samples 

 were highly colored, and the predominating odor is faintly earthy. 

 According to the standards of interpretation, Nos. i and 2 were in good 



