1714 Journal of Applied Microscopy 



[ NEWS AND NOTES. 1 



American Microscopical Society. — Descriptions of the special apparatus 

 used in collecting the samples and of the methods employed are given. 

 The physical examination includes temperature, appearance, turbidity, color, 

 and odor. The factors of the chemical analysis are nitrogen as albuminoid 

 ammonia, nitrogen as free ammonia, nitrogen as nitrites, nitrogen as nitrates, 

 residue on evaporation, loss on ignition, chlorine, hardness, alkalinity, in- 

 crusting constituents, iron, oxygen consumed, dissolved oxygen, and car- 

 bonic acid. The microscopical examination determines the number and kinds of 

 microscopic organisms present, together with the amount of amorphous matter. 

 The number of bacteria present is determined by a quantitative test, the only 

 bacterial organism which is especially looked for being Bacillus colt comvtunis, 

 The paper closes with some observations on the microscopic forms which have 

 been found to be of sanitary importance, especially Asterionella, Synedra pulchella. 

 Cyclotella, Melosira, and Analuena, all of which have been found to be instrumental 

 in the production of unpleasant tastes or odors, or both. The paper is illustrated 

 by four plates, showing views and the plan of the laboratory, and the seasonal 

 variation in number of some of the more important organisms. 



The paper on " Methods of Producing Enlargements and Lantern Slides of 

 Microscopic Objects for Class Demonstration," by John Aspinwall, is so full of 

 technical directions that no abstract will do it justice. The writer uses the Paget 

 plate, made in England, and seeks to avoid the glaring black-and-white effect so 

 characteristic of ordinary slides. The object of the method is " to produce 

 photomicrographs of considerable magnification, and yet of great depth of focus, 

 while using lenses of high resolving power." 



" On the Distribution of Growths in Surface Water-Supplies and on the 

 Method of Collecting Samples for Examination," by Frederick S. Hollis, is a 

 study of the seasonal distribution of the microscopic organisms found in the 

 eight reservoirs of the Metropolitan Water Works. These reservoirs vary from 

 fifteen to sixty feet in depth and contain from a third of a billion to seven and 

 one-half billion gallons of water. The organisms were counted in samples taken 

 from the surface, mid-depth, and bottom. It was found that in general the num- 

 ber of organisms present was greater in the reservoirs through there was a fairly 

 marked fiow of water as compared with those in which the currents were not so 

 noticeable. At the time of the autumn and spring overturn the organisms are 

 found to be very evenly distributed vertically throughout the water. The paper 

 is accompanied by four charts showing the variation in abundance, during five 

 years, of the organisms at the surface, mid-depth, and bottom, for several of the 

 reservoirs, the variation of tempratures in Lake Cochituate for 1896, and the 

 variation in the color of the water of the same lake during that year. 

 University of Rochester. CharLES WriGHT Dodge. 



(Continued.) 



