DEAD ANIMAL MATTER. 105 



Beccaria and Reaumur made many attempts to 

 render the luminosity of the pholas permanent. 

 The best result was obtained by placing the dead 

 mollusk in honey, by which its property of emit- 

 ting light lasted more than a year ; whenever it 

 was plunged into warm water the body of the 

 pholas gave as much light as ever. 



Galeatus and Montius showed that vinegar and 

 wine extinguished the light of the dead pholades; 

 that a heat of 45 Reaumur (56 centigrade) ex- 

 tinguished this light, though it had increased in 

 intensity up to that temperature, and that it could 

 not afterwards be brought back again. 



Many other less remarkable experiments have 

 been noted by the above-named authors. 



Most saltwater fish become phosphorescent in 

 the dark, like those mentioned above ; and con- 

 cerning those which inhabit fresh water I have 

 heard it stated that the ovaries of the carp have 

 been seen in a phosphorescent state. 



Mr. Canton has observed that several kinds of 

 river fish could not be made to give light in the 

 same circumstances in which sea-fish became lu- 

 minous, but that a piece of carp made water very 

 luminous, though the outside or scaly part of it 

 did not shine at all. 



In 1672 Boyle published a paper in the ' Philo- 

 sophical Transaction s/ containing observations 

 upon shining flesh. He treats in this paper of the 



