upon Luminous Animals . 285 
Experiment 6.—' To satisfy myself how far the evolution of 
heat during the shining of glow-worms, depended upon the 
life of the animals, I cut off the luminous portion of the tail from 
several living worms, and I found that if the thermometer was 
applied to them immediately, it was raised by them one or two 
degrees ; but after these parts were dead, although they con- 
tinued to emit light, they produced no effect whatever upon 
the instrument. 
Experiment 7. — Some hemispherical medusae were put into 
a spoon, containing a small quantity of sea water, and held 
over a burning candle. As soon as the water became heated 
the medusae appeared like illuminated wheels, the spots at the 
margin and center alone emitting light ; in which manner 
they shone vividly and permanently for about so seconds, 
when they shrunk and died, after which they were no longer 
luminous. 
Experiment 8.* — Some of the same species were put into 
spirits: a strong and unremitting light was instantly given out, 
which issued from the central and marginal parts, as in the 
preceding experiment, and continued until they died. 
Experiment 9.— Some of the scintillating and hemispheri- 
cal species of medusa, contained in a small glass jar, were 
introduced into the receiver of an air pump, and the air being 
exhausted, they shone as usual when shaken ; if any difference 
could be perceived, the light was more easily excited, and 
continued longer in vacuum. 
I wished next to try the influence of electricity on the lu- 
minous property of animals. 
Experiment 10. — A medusa hemispherica was placed in 
a sir ail glass dish, containing a quantity of water, merely 
MDCCCX. P p 
