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perty voluntarily to extinguish, referable to some in- 

 scrutable power dependent on volition, and not, as was 

 advocated by Carradori, by retracting it under a mem- 

 brane : when he extracted the latter from living glow- 

 worms, it afforded no light, while the two sacs in like 

 circumstances shone uninterruptedly for several hours. 

 The reason, however, of the apparent extinction of 

 the luminous matter in the penultimate and ante- 

 penultimate annuls, we have found to be the envelope- 

 ment of the luminous matter by the surrounding inter- 

 stitial mass, and if it be carefully sought for, it will be 

 found deeply imbedded in it : this is the reason of the 

 eclipse. Mr. Rogerson says the eggs of the insect are 

 luminous, and we have certainly found luminous matter 

 excreted from the glow-worm. This occasionally 

 displayed, and oftentimes merged and lost in the 

 commoninte rstitial mass, may be the ova ; at any rate, 

 when the luminous matter is found, it appears under 

 the form of a congeries of minute brilliant points. 

 Mr. Macartney is of opinion that the interstitial sub- 

 stance which surrounds the oval yellow masses under 

 the transparent spots in the thorax of the elater nocti- 

 lucus has the power of exhibiting light; in which 

 inference he considers himself warranted from the 

 radiated structure of this substance conjoined with the 

 translucency of the adjoining crust. This observer 

 was unable to conclude upon the peculiar organisation 

 that contributed to the efflux of light in the hollow 

 projections offulgora lanternaria and candelaria, the 

 hollow antennae ofpausus sphcerocerus, and that under 

 the entire integument of the scolopendra electrica. 

 Respecting the scolopendra electrica, he conceives that 

 it will not shine unless it be previously exposed to solar 

 light this conclusion is, however, not warranted by 

 the premises. He has even in other cases inferred 



