372 MisceUaneoufi. 



On the Luminosity of the Glow-worm (Lampyris splendidula). 

 By M. WiLHELM Kaiser. 



On June 26, 1884, I captured a particularly fine female speci- 

 men, 13 millim. long, of Lampyris splsndidula, Linn. For the 

 purpose of preparation I stupefie.d it with, ether, cut off its head, 

 opened the abdomen, pressed out several hundred eggs, and finally 

 prepared the luminous organ by cutting out the luminiferous papillae, 

 together with the chitinous substratum and a portion of the ventral 

 chain. The organ had previously shown no luminosity ; but when 

 I spread it out upon an object-slide furnished with a caoutchouc 

 ring, and, in applying the glass cover, brought it somewhat into the 

 shade, I observed that first one, then a second, and, lastly, the 

 third and fourth luminiferous papillaj shone with a green light. I 

 now applied two wires from a powerful galvanic battery to that part 

 of the preparation where I believed there were still remains of 

 nerves, but without thereby causing any alteration in the intensity 

 of the light. I then closed the preparation by applying Canada 

 balsam to the edges of the caoutchouc ring and fixing on a glass 

 cover. After this closure the organ continued shining for a quarter 

 of an hour. A quarter of an hour later I warmed the preparation 

 to about 50° C. ( = 112*^ F.), and then the luminosity gradually be- 

 came fainter, passing finally into a yellow flicker like that of touch- 

 wood, and then ceasing. I now opened the balsam closure again 

 and moistened the preparation with a drop of water. The luminous 

 organ then, in about five minutes, showed a faint green luminosity, 

 and it is still shining, an hour after the dissection, with a dull green 



I communicate this, as the current opinion, to be found even in 

 the best works, is that with the death of the animal the luminosity 

 ceases. This supposed fact, however, seems to sink into a mere 

 supposition in presence of my observation, unless the luminous 

 organ as such carries on an independent life for an hour after the 

 death of the animal, and during this continues to shine, whilst the 

 animal, when alive, has it in its power to shine or not. However, 

 1 leave it to experienced naturalists to repeat my experiment and 

 to test its relevancy to the question whether it is the decomposition 

 of a substance in the luminous organ or the so-called " transparent " 

 cells in that organ that produce the light, or what other forces may 

 come into play. I will only remark further that the luminosity of 

 animals, like other cases of mimicry, seems to serve for protection, 

 in order to deter other animals from devouring them at night ; thus, 

 if one seizes a non-luminous female glow-w^orm with a pair of for- 

 ceps, it immediately begins to shine, as also when it is roughly 

 dropped upon the ground. — Anztigcr der l\ Alcad. der Wiss. in 

 Wien, July 3, 1884, p. 133. 



