In a letter of March 12, 1880, Prof. E. T. Cox gives the following: “I fully believe that whenever any form of disease rages as an epidemic in any locality, it is due in a large measure to water pollution. The three streams of subterranean water beneath Indianapolis, flow from northeast to southwest. Wells that are supplied from the upper water, contain more and more chloride of sodium (common salt) as you go to the south part of the city, and this is absolute proof of sewer-pollution, and all the well water from the first and second seams is absolutely dangerous, and its use should be prohibited. The lower stratum is safe if the upper seams are shut off from it. When water works were first contemplated at Indianapolis, I was called upon for information, and had my advise been taken, you would now have the best possible water, instead of water of doubtful character, to use the mildest term.” On the 20th of March a sample of water was obtained from the water works for examination. The analysis showed in one litre, Total solids, .985 gramme Organic and volatile, .08 ” Chlorine, .055 ” Fifty centimetres of the water required fourteen drops of the permanganate of potash solution to render it permanently red. The same amount of distilled water required but eight drops. The microscope, with a lens of 100 diameters, revealed considerable vegetable matter. Inasmuch as White river is used by the water works as a source of supply when the water in their wells get low, and also in time of fire in the city, it was thought advisable to ascertain the condition of the river water. Therefore, on April 30, 1880, a sample was drawn from the river at middle of the iron bridge at the foot of Washington street. One litre contained: Total solid constituents .36 gramme. Organic and volatile matter .032 ” Chlorine .105 ” Free ammonia .00072 ” Albuminoid ammonia .00048 ” Fifty cubic centimetres of this water required thirty-six drops of the permanganate of potash solution to render it permanently red. The same amount of distilled water required but eight drops of said solution to become permanently red. The microscope revealed sand, clay, legs, and other parts of insects, foreign matter of many kinds, and animalculæ. This water is but little better than sewage. It is due to the water works to state that the water taken from the river is filtered through a bed of sand and gravel about four feet deep. Professor Edward R. Taylor, of Cleveland, examined two samples of water from the water works with the following result: