40 The Sea 
of little use to him. Still other animals are provided with spe- 
cially developed light organs—almost like little headlights— 
complete to reflectors, lenses and all! 
The process by which this light is produced appears to be 
the slow burning of a chemical substance called luciferin. 
The reaction is peculiar because light is given off rather than 
heat, as is the case in most chemical reactions. 
An experiment that you may perform, which duplicates to 
a certain extent the natural process of bioluminescence, is 
included here. Get two jars. Fill one jar half full of water, add 
a tiny pinch of sodium hydroxide; then stir in carefully a very 
small trace (about as much as will cover the end of a match- 
stick) of Luminol (not to be confused with the sleeping 
medicine luminal) which you can obtain from any chemical 
supply house. In the second jar place some crystals of potas- 
sium ferricyanide, and fill the jar half full with hydrogen 
peroxide (the 3% kind that platinum blondes use). Let the 
solutions stand for about one minute. Then, in a darkened 
room, empty the contents of the first jar into the second. 
There will be a bright flash of “cold” light, and the liquid 
will remain luminescent for many minutes. A very weird ef- 
fect is produced as you pour the bright liquid from one con- 
tainer to another in the dark. 
Just why sea animals light themselves up in such a spec- 
tacular way is not completely understood; however it is evi- 
dent that some are able to attract food into their mouths by — 
use of the light, whereas other fish actually use the light to — 
help them see around in the darkness of the ocean depths, 
just as divers use an electric torch. 
