188 



SCIENCE 



[N. S. Vol. L. No. 1286 



difficulty in presentation. Professor Whipple 

 has made it an attractive group of chapters, 

 •well written and even interesting. 



Pages 100 to 458 are, in effect, a discussion 

 of American demography. The chapters cover 

 the methods of enumeration and registration; 

 the characteristics of population; death rates, 

 birth rates and marriage rates; specific death 

 rates; causes of death, with especial reference 

 to particular diseases and for specific age 

 periods. Three chapters entitled, Probability, 

 Correlation and A Commencement Chapter 

 close this section of the book. 



The elementary facts of the vital statistics 

 of the United States are clearly presented in 

 the above chapters. In fact, the author 

 makes a special effort to hold his reader by 

 simplicity, clearness and force of statement. 

 Professor Whipple's book will not prove a 

 difficult one for the student. It does not at- 

 tempt too much along lines of thoroughness 

 of treatment. Only the high spots are touched. 

 Therein lies its value and perhaps also its 

 danger. For while this book will undoubt- 

 edly increase the skiU of the health officers 

 in the presentation of their reports, it may 

 also give many a feeling of competence greater 

 than is justified by their skill. One would 

 have wished that tuberculosis, cancer and a 

 few other of the more important diseases had 

 been treated more thoroughly in the light of 

 recent contributions on these diseases. These 

 could then have served as general models for 

 the discussion of diseases as causes of sick- 

 ness and death. In fact, the author has paid 

 too little attention to the very important sub- 

 ject of the classification of the causes of 

 death. This should be a vital matter to all 

 health officers if they are to publish accurate 

 statistics of the mortality of their respective 

 communities. It is also characteristic of this 

 book that the discussions are somewhat dis- 

 jointed, perhaps because of the desire of the 

 author not to overstrain the attention of the 

 reader. We often find a subject treated in a 

 number of places where a more continuous 

 discussion would have left a clearer im- 

 pression. 



Altogether, this is a useful first course 



which, under competent laboratory instruc- 

 tion, should add materially to the popularity 

 of vital statistics among health officers and 

 others engaged in developing the public health 

 movement in the United States. Professor 

 Whipple will have earned the gratitude of 

 those engaged in public health work if the 

 book does what is hoped for it. This may be 

 some compensation for the time which he, as 

 a busy sanitarian, must have taken from his 

 work in order to have made this text-book 

 possible. 



Louis I. Dublin 

 1 Madison Avenue, 

 New Yoek City 



A HISTORICAL NOTE ON THE 



SYNCHRONOUS FLASHING OF 



FIREFLIES 



The interesting accounts of this remark- 

 able habit published in Science during the 

 past two years by Professor E. S. Morse and 

 others have led me to make notes of similar 

 accounts found in working up certain books 

 on the East Indies and ISTew Guinea. The ex- 

 cellent summary of our knowledge of this 

 striking phenomenon published in Science for 

 July 26, 1918, by Professor Morse, and the 

 later communication from Mr. George H. 

 Hudson led me to believe that these histor- 

 ical data may be of interest and possible value 

 to those studying this habit in insects. 



The first of these accounts was found in 

 Robert W. C. Shelford's book " A ISTaturalist in 

 Borneo" (London, 1916), a work replete with 

 natural history data of great interest and 

 value. At the time that I made a note of 

 Shelford's observations, I had forgotten that 

 Professor Morse in Science for September 15, 

 1916, had published Shelford's account from 

 advance proof sheets of his book. 



The next account I have chanced upon is 

 from the pen of ISTelson Annandale, the well- 

 known zoologist of Calcutta, India. His paper, 

 " Observations on the Habits and Natural 

 Surroundings of Insects," made during the 

 " Skeat Expedition " to the Malay Peninsula, 

 1899-1900 was published in the Proceedings 

 of the Zoological Society of London, 1900. 



