ON LUMINOUS ANIMALS. - 45 



of the insect put it out of my power to examine its struc- 

 ture, but from the form and situation of its organs of light, 

 it is most probable they are constructed like those of the 

 fulgoiae. 



It has been conjectured by Carradori and others, that The light regn- 



the larapyrides were enabled to moderate or extinguish their ^?^!},^^ 



"^ , , any visible 



light, by retracting the luminous substance under a mem- mechanism, 



brane ; but neither in them, or any of the other luminous 

 insects, have I found an apparatus of this sort. The sub- 

 stance furnishing the light is uniformly applied to corre- 

 sponding transparent parts of the shell of the insect, whence 

 it is not moved ; indeed a membrane, if it did exist, would 

 have but little effect m obscuring the light, and never could 

 serve to extinguish it. The regulation of the kind and 

 degree of the luminous appearance does not depend upon 

 any visible mechanism ; but, like the production of the ^"^ ^y some 

 light itself, is accomplished by some inscrutable change in fu,ninouTmiit- 

 the luminous matter, which in some animals is a simple ter. 

 operation of organic life, and in others is subject to the 

 will. 



It is worthy of remark, that, in all the dissections I have The light of 

 made of luminous insects, I did not find, that the organs ms^cts uncou- 

 of light were better, or differently supplied with either nervous euer- 

 nerves or air tubes, than the other parts of the body. The gy* 

 power of emitting light likewise exists in many creatures 

 xvhich want nerves, a circumstance strongly marking a dif- 

 ference between animal light, and animal electricity. 



With the exception of the animals above mentioned, the In other ani- 



exhibition of light depends upon the presence of a fluid "'^^^s the lumi- 

 ° * *^ * nous matter is 



matter. fluid: 



In the pholas dactyl us, the luminous fluid is particularly as in the pho- 

 evident, and in vast quantity; it is recorded by Pliny, that l^sductjius} 

 this fluid is like liquid phosphorus, and renders every ob- 

 ject luminous, with which it conies into contact. Reaumur 

 also found, that it was ditfusible in water, or any other 

 fluid, in which the animal might be immersed*. 



The shining of the scolopendra electrica I have always scolopendra 

 observed to be accompanied by the appearance of an effu- *^''^^"^^^' 



♦ M^m. de TAcad. des Sc. 1712. 



•ion 



