PAPERS OX PSYCHOLOGY AND PHYSIOLOGY 115 



ance in the sense of a by-product. And it is furtheiTQore 

 apparent from the researches of Harvey (12) that the 

 release may be very regular provided that the physico- 

 chemical conditions are such that the oxidation of luci- 

 ferin can be resumed at jDeriodically recuning intervals. 

 It is not necessary therefore to take the extreme view 

 that the flashing is due to movements of the eyelids of 

 the observer, as Laurent concluded (15), or that the mat- 

 ter rests largely upon the suggestion of the obsei^ver's 

 mind as Craig infers (9). or that, as Gates remarks (10), 

 *'comi3lete synchronism in the flashing of a group of fire- 

 flies is simply a very rare accident, occurring -when the 

 flashes of the individuals chance to come at the same 

 time. ' ' 



II. EXPEKIMEXTAL 



The writer believed that, aside from the vaiying cir- 

 cumstances attendant upon the obsei-vations as noted, a 

 reasonable item in the explanation of the phenomenon in 

 its psychological aspects was the well-known tendency 

 of the human mind to integrate its experiences. If the 

 ticks of a metronome are heard at first in a monotonous 

 and unaccented fashion, soon they will be measured off 

 subjectively into groujDS; if any unevenness should occur 

 in these beats, it would be overlooked and the grouping 

 would continue as before ; and if a number of metronomes 

 were set off at respectively dift'erent rates, the subject 

 hearing them all at once would bring order out of chaos 

 and begin to superimpose a grouping on the irregularly 

 beating complex. 



The assumption made, then, was this : suppose, as some 

 writers stated, there should be several coincidences 

 among a large number of firefly flashings in a given place. 

 This would be so striking that the periods of darkness 

 might seem in comparison more or less complete; and it 

 would then tend to set the mind of the observer in the 

 direction of subsequent grouping of flashes in patterns 

 supplied, for the most part, by himself. In the case of 

 observers whose rhythmicizing tendencies were not so 

 strong — they are never entirely wanting in the normal 

 human mind — the report would take a ditferent turn 



