144 



discerned, burying it in the interstitial matter, or 

 secreting it under an opaque shell. 



III. The light is not connected with any of the 

 functions of animal life, as to its support or continu- 

 ance, such as the spiracula or breathing apparatus, 

 though it be so indirectly through the medium of the 

 circulation, and to which its variable intensity seems 

 attributable ; and even the extinction of life itself 

 does not extinguish the power and property of emit- 

 ting light. 



IV. The luminous matter is not adherent exteriorly, 

 but included in a capsule, which preserves it from 

 extrinsic agency and contingency. 



V. The light seems associated with peculiar organ- 

 isation, which elevated temperatures destroy, perhaps 

 by decomposition, but which low temperatures only 

 temporarily suspend. This very suspension, indeed, 

 by cold, and restoration by warmth and by a tempera- 

 ture equal to that of animal heat, goes far to prove a 

 peculiar function, inherent in the capsule, capable of 

 educing and sustaining the phenomenon. 



Mr. Spence, in a communication to Mr. Loudon *, 

 states, that Dr. Carus of Dresden has made the dis- 

 covery, that there is a connection between the circu- 

 lation of the blood in the lampyris italica and the 

 luminous matter which occupies a great part of the 

 under side of the abdomen, and that the varying in- 

 tensity of the light is thus produced, the greater in- 

 tensity corresponding precisely with each pulsation of 

 that fluid, being from 44 to 54 times in a minute, when 

 the insect is not disturbed, but more rapidly and 

 irregularly when alarmed : we are informed that the 

 gleams of light in the fulgora lanternaria also vary 

 in intensity, and doubtless the cause is a similar one. 

 * Magazine of Natural History, No. XL p. 49. 



