July 13, 1900.] 



SCIENCE. 



69 



to shirk effort altogether by accepting phrases 

 which cloak the unknown in the undefinable." 

 Others again may object to the particular 

 make-up of this ' Grammar ' ; may question 

 whether the long discussion of the quantitative 

 aspects of evolution (a novel feature of the 

 second edition) however interesting in itself, 

 finds a coordinate place with the rest of the 

 chapters, or whether it represents unduly the 

 special trend of the writer's interests. But no 

 critic can fail to find the general treatment rig- 

 orous and suggestive, and to feel that the possi- 

 bilities of presenting the fundamental concep- 

 tions of science to the student have been 

 appreciably increased by Professor Pearson's 

 labors in his behalf. Joseph Jasteow. 



The Microscopy of Drinking Water. By George 

 Chandler Whipple. New York, John 

 Wiley & Sons. 1899. Pp. xii + 300. With 

 21 figures and 19 half-tone plates. 

 The biological examination of potable water 

 has been conducted upon an extensive scale in 

 this country for more than a decade, especially 

 in Massachusetts where the State Board of 

 Health and the City of Boston have maintained 

 laboratories for the scientific investigation of 

 water supplies. It is fitting, therefore, that the 

 first extensive hand-book upon the subject of the 

 microscopy of drinking water should have been 

 written by one long associated with this work. 

 Mr. Whipple's ' Microscopy of Drinking 

 Water,' is more, however, than a mere manual, 

 for it presents the generalization derived from 

 the explorations and statistical data accumulated 

 by the State Board of Health, the Boston, and 

 more recently the Brooklyn Water Works for a 

 series of years. It thus treats of many problems 

 of limnology and fresh water biology of interest 

 not only to the sanitary engineer and water ex- 

 pert but to the biologist and physicist as well. 

 The opening chapter is devoted to a his- 

 torical treatment of the subject in which the 

 faunistic and systematic biology of fresh water, 

 and planktology also, are included. The treat- 

 ment is brief and there are many omissions. 

 There is, for example, no mention of recent 

 investigations of water supplies in European 

 cities, nor is any reference made to the lacus- 

 trine explorations of the United States Fish 



Commission in past years. The excellent work 

 of the Bohemian Survey and of the Balaton 

 Lake Commission in Hungary is unnoticed. 

 Hensen, the father of planktology, is referred 

 to as having devised a ' new method of study- 

 ing the minute floating organisms found in 

 lakes ! ' The planktonocrit is ascribed to 

 Dolley, and the Plankton pump to Ward and 

 Fordyce. The first use of the centrifuge in 

 plankton work seems to have been made by 

 Kramer or Cori, and the pump for the col- 

 lection of plankton was used by Henson, by 

 Peck, at the Illinois Biological Station, and by 

 Frenzel, before the pump named was described- 

 Bacterial examination is not treated in the 

 work as its methods are difierent and involve 

 other processes than microscopical examination. 

 The purpose and relative values of the various 

 forms of sanitary examination are discussed at 

 length by the author. The physical, biological 

 and chemical analysis of water supplies are 

 each important, and are mutually supple- 

 mentary. The interpretation of an analysis 

 is a matter of expert skill quite as much as the 

 making of the analysis. "In the detection of 

 pollution the chemical and bacteriological ex- 

 aminations furnish the most information, in the 

 study of the sesthetic qualities of a water the 

 physical and microscopical examinations are 

 most important, while in investigations con- 

 cerning the value of a water for industrial 

 purposes the physical and chemical examina- 

 tions sometimes suflice." The purposes of 

 microscopical examination are stated to be the 

 detection of sewage pollution, the explanation 

 of turbidity, of taste and of odor of water, 

 the interpretation of chemical analysis, and the 

 study of food of fishes and other aquatic ani- 

 mals. The most important service which the 

 microscopical examination of potable water ren- 

 ders is thus in the study of its aesthetic qualities. 

 The Sedgwick- Rafter method of water exam- 

 ination is described with its various modifica- 

 tions and improvements, and the errors incident 

 to its use are discussed. The error from leak- 

 age through the sand may rise as high as 25 

 per cent, or even 50 per cent, when minute 

 organisms are present in large numbers, and 

 the statement is made that most of the escap- 

 ing organisms pass through the sand in the 



