BY INFERIOR ORGANISMS. 123 
ralists, who made a scientific voyage round the 
world in the ship ‘ La Bonite,’ observed that cer- 
tain small phosphorescent Crustacea sometimes 
secrete a peculiar phosphorescent matter, and 
that when they are irritated, they send forth mag- 
nificent flashes of light. Other crustaceans did 
not appear to possess this faculty. These two 
gentlemen collected a certam quantity of the 
phosphoric substance ; they found it to be “ yel- 
lowish, viscous, and soluble in water,’ communi- 
cating its luminous property to this liquid, but 
only for an instant or two. It lost its luminosity 
when it had been separated for a few moments from 
the body of the animal. 
These naturalists have also observed the phe- 
nomenon of phosphorescence in certain Pteropoda 
and Cephalopoda ; they believe that these animals 
possess a peculiar phosphorescent substance lke 
that of the Crustacea, which, from their observa- 
tions, appears to be continuously and uniformly 
luminous as long as the animals live, but ceases 
to be so when they die. 
When the phosphorescent Infusoria, of which 
I have spoken, are exhausted and cease to emit 
any light, their luminous faculty can be restored 
for a while by exciting them with a drop of dilute 
> acid or alcohol mixed with the sea-water; but 
this experiment soon kills them. 
Humboldt affirms that having placed certain 
