The fact that foul water will breed disease, should no longer be ignored. The citizens of Indianapolis have been drinking water from the city water works not above suspicion, and it is about time that the pollution of the water by filth should excite public attention. Below I give analyses of samples of water drawn at different times and places from the faucets of the city water works. The following report is from Prof. Thos. C. Van Nuys, of the State University. BLOOMINGTON, Ind., May 10, 1880. The water you sent on Thursday was received on Friday evening. The following is the report of my chemical and microscopic examinations: In one litre (1,000 cubic centimetres). Nitric acid anhydride, N₂O₅. 10.72 milligrammes Ammonia, NH₃, 0.03 ” Carbonic acid anhydride, CO₂. 0.439 gramme. Calcium oxide, CaO, 0.148 ” Magnesium oxide, MgO, 0.04128 ” Chlorine, 0.09218 ” Degree of hardness (English) 25.7 The organic matter in 100 cubic centimetres of the water required 3.11 cubic centimetres of the 1-100 normal solution of potassium permanganate to oxidize it; therefore one litre of the water would require 31.1 cubic centimetres of the 1-100 normal solution KMnO₄ to oxidize the organic matter. In 31.1 c. c. of this solution there is 0.0098 gramme KMnO₄ or 0.0247 gramme oxygen liberated. I would remark here that there is no method of estimating the exact quantity of organic matter in water. The method of estimating the carbon and hydrogen by combustion analysis (Frankland and Armstrong’s) has been found defective,—also the methods based on the estimation of nitrogen and reduction of silver oxide. The method employed in this case (Schultze’s) is the most reliable, and yet not all the organic matter is oxidized, for some is volatized in boiling. I found the following infusorial animalaculcæ: Stylonchia pustulata, actinurus neptunius, rotirfer vulgaris, monostylaquadridentata, navicular baltica. I give here the magnified pictures. [Illustration: Actinurus Neptunius.] [Illustration: Navicula Baltica.] [Illustration: Monosty la Quadridentata.] [Illustration: Rotifer Vulgaris.] [Illustration: Stylonchia Pustulata.] I did not examine the first sample of water with the microscope. In the water of the second bottle I found but one kind of infusoria, _viz._, stylonchia pustulata, but they were numerous. In the water sent on Thursday I found the others named, but few in number. In both samples of water there was but a small quantity of mineral matter, a few crystals of CaCO₃. The water was somewhat cloudy and the suspended particles were evidently of vegetable origin. I have not adopted any standard in judging water for drinking purposes.