NOVEHBEB 10, 1916] 



SCIENCE 



683 



over a wide area. Miners in this part of 

 British Columbia believe that in the winter a 

 particularly brilliant display of the aurora is 

 likely to be followed by a heavy fall of snow, 

 but I am unable to determine how far the 

 actual records bear out this belief. 



M. H. Jacobs 

 University of Pennsylvania 



SCIENTIFIC BOOKS 



The Life of Inland "Waters. An elementary 

 text-book of fresh-water biology for Amer- 

 ican students. By James G. ISTeedhaji:, Pro- 

 fessor of Limnology in Cornell University, 

 and J. T. Lloyd, Instructor in Limnology 

 in Cornell University. Octavo of 438 pages 

 with 244 illustrations. 1916. The Corn- 

 stock Publishing Company, Ithaca, !N"ew 

 York. 



Needham and Lloyd have produced a very 

 good and very useful book. It is well planned, 

 well executed and well illustrated. It deals 

 with the life of fresh water — chiefly the micro- 

 scopic forms and the insects — from the point 

 of view of environment and mutual adjust- 

 ment. It is, therefore, not a handbook for 

 identifying forms, nor is it a treatise on 

 limnology and its methods, or even on fresh- 

 water biology. It is not a "popular" book, 

 to be read with full intelligence and interest 

 by a person ignorant of biology and of fresh- 

 water life in particular. It is rather a book to 

 accompany the study of fresh-water biology 

 in laboratory and in tbe field. It gives the 

 general points of view, the grouping and cor- 

 relation of facts, which such a student needs 

 if he is not to become entangled in a hope- 

 less web of details. This it does in moderate 

 compass and with sufficient detail to make the 

 principles clear, definite, and, therefore, use- 

 ful to the student. 



The subject is handled under four main 

 heads : (1) the nature and the types of aquatic 

 environment; (2) aquatic plants and animals; 

 (3) adjustment of plants and animals to con- 

 ditions of aquatic life and to each other in 

 aquatic societies; (4) inland water culture. 

 The reviewer finds the fourth head the least 



interesting, though not the least important 

 from a practical point of view. Less has been 

 done and, therefore, there is less to be said 

 about this matter as yet. The third head 

 (Chapters V. and VI.) shows the book at its 

 best. The interrelation of plants and animals 

 and the adjustment of both to environment 

 are here discussed. Chapter V., for instance, 

 treats first of individual adjustment to 

 aquatic life, whether in open water or on the 

 bottom. Methods of floating, swimming, etc., 

 are described for the open-water forms, and 

 methods of burrowing, shelter building, mo- 

 tion on and through the mud, etc., for the 

 bottom forms. Adjustment of the life cycle 

 to seasonal changes in the aquatic environ- 

 ment is then considered, involving such mat- 

 ters as statoblasts and winter eggs. Mutual 

 adjustment is briefly treated and illustrated by 

 the insectivorous marsh plants and by the 

 larval habits of mussels. Chapter VI. deals, 

 first, with limnetic societies, primarily divided 

 into those of open water and those of the 

 shores. The former includes the plankton 

 (persistently spelled "plancton" by the 

 authors — doubtless with reformers' inten- 

 tions) ; the latter set includes the shallow- 

 water societies passing into those of ponds, 

 pools and marshes. The chapter concludes 

 with an account of the lotic societies, or those 

 of streams. All of these forms of association 

 are well described and especially well illus- 

 trated. 



Of course any specialist will see places 

 where he would have written the book differ- 

 ently, and places where he would have enlarged 

 or reduced the space given by the authors. 

 One must regret that the fascinating and valu- 

 able subject of mutual adjustment is so briefly 

 treated. The emphasis on insects will seem 

 somewhat disproportionately large to students 

 of other groups. It seems to the present 

 reviewer that the account of physical condi- 

 tions of life in lakes has not the vigor of the 

 ecological chapters. Here and there the sub- 

 ject is somewhat fumbled, as in the treatment 

 of lake temperatures. The summer tempera- 

 ture conditions of Cayuga Lake, shown in 



