RECENT ADVANCES IN OUR KNOWLEDGE OF THE PRO- 

 DUCTION OF LIGHT BY LIVING ORGANISMS. 



By F. Alex. McDermott, Washington, D. C. 



INTRODUCTION. 



The original paper C 8 ) 1 upon which the following is based was read 

 under the title " The Chemistry of Biophotogencsis," before the Chem- 

 ical Society of Washington, D. C, on October 13, 1910, and subse- 

 quently published in the Scientific American Supplement, No. 1842. 

 In revising this paper for publication here it has been found that so 

 much new work of importance has been published or has come to the 

 author's attention in the interim, that it has been decided to recon- 

 struct the paper along the line indicated by the above title, taking up 

 the more significant recent work, and adding a few heretofore un- 

 published observations of the author. 



The term "Biophotogenesis," in its complete sense of the produc- 

 tion of light by living organisms, covers a group of phenomena accom- 

 panying the vital processes in a wide range of animal and vegetable 

 forms. . The fireflies (Lampyridae) are to most of us the commonest 

 and most brilliant of these forms, and the following will therefore have 

 special reference to these insects. 



An excellent monograph ( 45 ) of the subject of the emission of 

 light by living forms, including an extensive bibliography of the 

 important papers and a general review of the literature, has appeared 

 under the title "Die Produktion von Licht," by Prof. E. Mangold, as 

 the second half of the third volume of Winterstein's Handbuch der 

 vergleichende Physiologie. The whole literature of the subject is 

 very extensive, although much of the older work is without signifi- 

 cance to-day. A considerable number of scientific men, including 

 workers in the fields of chemistry, physiology, biology, entomology, 

 and physics, are working on the problems presented by the phenomena 

 of luminous organisms, and important developments in our knowl- 

 edge of this subject are to be expected. 



: Numbers refer to literature references at the end of paper. 



345 



