222 



SCIENCE 



[N. S. Vol. XXXIII. No. 841 



plant for a few days were again offered to the 

 lizard, which ate them readily. Thus it is 

 shown that a mere change of food plant may 

 be of great importance in relation to destruc- 

 tion by natural enemies; furthermore, that 

 some distasteful larvse do not possess " war- 

 ning " coloration, and again, that these 

 cryptically colored larvse were not recognized, 

 after a few days, as objectionable. It would 

 be interesting to repeat the experiment, hav- 

 ing, if possible, ornamented the larvae in some 

 way so that they would be more easily recog- 

 nized. 



t. d. a. cockerell 

 University of Colobado 



Sewage Disposal. By Leonard P. Kinnicutt, 

 Director of the Department of Chemistry, 

 Worcester Polytechnic Institute; C.-E. A. 

 WiNSLOW, Assistant Professor of Biology 

 and Biologist in charge of the Sewage Ex- 

 periment Station of the Massachusetts In- 

 stitute of Technology, and E. Wintheop 

 Pratt, Chief Engineer of the Ohio State 

 Board of Health, late director of Sanitary 

 Engineering of the Eepublic of Cuba. 

 New York, John Wiley & Sons. Price, $3. 

 This octavo book of 421 pages consists of a 

 well-blended recital of American and Euro- 

 pean, especially English, experiences which 

 have established the principal features now 

 recognized in the science and art of sewage 

 disposal. Almost without exception it is free 

 of views that are either radical or so old-fash- 

 ioned as to be regarded as superseded. 



The joint authorship of this book has much 

 to commend it and it will be noted that it 

 includes in Professor Kinnicutt one of the 

 foremost sanitary chemists in America, and 

 one who has been fortunate enough to make 

 numerous inspection trips to sanitary works 

 in Europe, during the past thirty years. Pro- 

 fessor Winslow, formerly of the Institute of 

 Technology, in Boston, now of the College 

 of the City of New York, has had unusual op- 

 portunities of studying the biology of this 

 subject, particularly in connection with exten- 

 sive experiments made at Boston. .The prac- 

 tical side, from an engineering standpoint, 



has occupied the attention of Mr. Pratt for 

 many years, first in Massachusetts and later 

 in Ohio, with a valuable experience in Cuba. 



The chemical and biological aspects of the 

 book are more comprehensive and detailed 

 than those of an engineering nature. Prob- 

 ably this is wise in a book of this size on a 

 subject of such a wide scope as this one and 

 which is undergoing such rapid changes in 

 some of the more important aspects of engi- 

 neering practise. Numerous references are 

 given to details of results obtained from the 

 findings of the Royal Commission on Sewage- 

 Disposal of Great Britain, as well as the re- 

 sults of tests and practical operations in. 

 America and abroad, especially in England.- 

 References are rather meager as to German 

 investigations and experiences. To some ex- 

 tent the same is true of the results of current 

 practise in the design and operation of dis- 

 posal works in the United States other than in 

 Massachusetts and Ohio. 



After an interestingly stated introduction 

 as to the sanitary demand for sewerage and' 

 sewage disposal, the book is divided intO' 

 thirteen chapters, of which brief mention may 

 be made to advantage as follows : 



Chapter 1, pp. 1-20, deals with the compo- 

 sition of sewage in the terms of the analyst. 

 Chapter 2, pp. 21-44, outlines the disposal of 

 sewage by dilution. Chapter 3 gives many 

 details as to the screening and straining of 

 sewage, pp. 45-67. 



The preliminary treatment of sewage by 

 sedimentation, chemical precipitation and 

 septic process occupies Chapters 4, 5 and 6, pp. 

 68-166. These chapters are unusually well- 

 written, although they do not bring fully up> 

 to date very recent developments with the so- 

 called " Imhoff " tanks, which have shown 

 themselves to be a marked step in advance- 

 during the past year or two in practical opera- 

 tions in western Germany. 



The expensive, bothersome and frequently 

 unsuccessfully solved question of the disposal 

 of sewage sludge is well outlined on pagea 

 167 to 192. 



Chapters 8 to 11, inclusive, on pages 193- 

 274, contain a well-balanced statement of ex- 



