SCIENCE— ADVERTISEMENTS 



JUST OUT 



The Free-Living 

 Unarmored Dinoflagellata 



BY 



KOFOID AND SWEZY 



S62 quarto pages; 12 colored plates and 38S 



figures in text. Paper, $12.50. 



Carriage extra, weight 7 lbs. 



A monumental work on these elusive organisms, 

 based on years of observation off the coast of Cal- 

 ifornia, in the Eastern Tropical Pacific, and in the 

 plankton traverse of the Northern and Western 

 Pacific and Indian oceans. 



The work sets forth a summary of present know- 

 ledge, makes clear the causes of discolored seas 

 and phosphorescence of ocean waters, and offers 

 new conceptions of the relationships of genera 

 within the group. 



The University of California Press 



Berkeley, California 19 East 47th Street, New York 



Does it apply to modern conditions? 

 Is the test that a textbook must pass today 



GRUENBERG'S 

 ELEMENTARY BIOLOGY 



Fulfills this requirement. 

 Not biology as a sterile aca- 

 demic study is here under 

 consideration, but biology as 

 applied in terms of human 

 welfare. The principles dis- 

 cussed are immediately and 

 practically applied to prob- 

 lems affecting the well-being 

 of the individual, of the 

 community, indeed of the 

 race. The book provides a 

 sound basis for further study 

 in any science. 



GINN AND COMPANY 



70 Fifth Ave. New York 



Wiley Books For Public Health Officials 



Ready September I S^h 

 PUBLIC HEALTH SURVEYS 



What They Are. How to Make Them. How to Use Them. 

 By MURRAY P. HORWOOD, Ph.D. 



Instructor in Biology and Public Health, Massachusetts Institute of Technology. With a Fore- 

 word by the late William T. Sedgwick and an Introduction by George C. Whipple. 



A practical guide for health officers, boards of health sanitary inspectors, socio-sanitary and 

 welfare workers, students in schools of public health and investigators. 



403 pages. 45 by 7. 95 figures. Flexibly bound. 



Manual for Health Officers 



By J. SCOTT MACNUTT, A.B., S.B. 



A complete treatise on the duties and author- 

 ity of health officers. 



650 pages. 5} by 8. 4 charts. 

 Cloth, $4.00 postpaid. 



Vital Statistics 



By GEORGE CHANDLER WHIPPLE 



A guide to the study of vital statistics, for 

 students who are preparing themselves to be 

 public health officials. 



517 pages. 4 J by 6 J. 63 figures. 

 Flexibly bound, $4.00 postpaid. 



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