All available scientific data, both chemical and bacteriological, should be collected and studied before judgment is passed on a water supply used for food, and such should be systematically recorded by all water works companies. The nitrogen content of water and the chemical conditions in which this is found have long been considered very valuable, nor is there at present any good reason to discredit the use of such reports. All sanitarians are familiar with the gradual change of animal and plant nitrogen in the combined form until it reaches the inorganic nitric state, and the chemical changes will not be further discussed than to remark that unpolluted natural waters, with few exceptions, are remarkably free from nitrogen. The analyses1 are recorded to show how the waters of central New York differ in nitrogen content and in what state this element has been found. All tests have been made according to the methods prescribed by Wanklyn and Mason and are tabulated in parts per million. The total solids determination is the weighed residue from 50 cc. of water, evaporated to dryness on the water bath and placed in a desiccator over sulphuric acid for twelve hours. Chlorine has been determined volumetrically, according to Mason, unless above 50 parts per million, when the gravimetric method was employed. Free and