242 
POPULAR SCIENCE REVIEW. 
During the daytime, if Lamjoyris be watched, whilst under the 
shade, she is not luminous as at night, and it is difficult by 
irritation to get her to shine. Again, there is manifest paling 
of the light after midnight, and the neighbourhood of the male 
causes both to flash out more. The influence of nerve is the 
most manifest in the Insecta, less so when the structure is 
rudimentary in the Alcyonaria, and it is absent in Noctiluca . 
But still, as the simplest nerve is protoplasm differentiated 
slightly and formed into masses and long lines ; so even in 
Noctiluca , the light, situated as it is, at the very extremity of the 
thready protoplasm, which is ever streaming at its surface with 
granular matter, may be said to be in relation with localized 
potential, the energy of life. The phenomena of the so-called 
phosphori, or the luminosity of such substances as sulphide of 
barium, even when the emission of light is brief, is a conse- 
quence of molecular change and movement. Certain minerals 
obtain this movement after exposure to the sun, or to artificial 
but intense light, and in its production the energy of the light 
given has been transferred, and, as usual, more or less degraded. 
One can understand that if there is an energy of life, linked on 
to the unstable albuminoid, the basis of animal and vegetable 
organisms, and it can produce heat and electricity, it can, as 
the highest physical potential, produce molecular movement 
sufficient to develop light waves. 
EXPLANATION OF PLATE VI. 
Fig. 1. Noctiluca miliaris, magnified 100 diameters, showing the fibrillar 
structure; the flagellum^ (/) : and the cilium at the oral aper- 
ture (s). 
„ 2. Noctiluca miliaris , slightly magnified and luminous. 
„ 3. Noctiluca miliaris, luminous portion highly magnified. 
„ 4. Phyllirhoe bucephala, showing^the luminous spots. 
„ 5. Pyrosoma giganteum, reduced in size. 
„ 6. Lampyris noctiluca, female, natural size. 
„ 7. The same ; the luminous organs enlarged. 
„ 8. The male, its luminous organs magnified. 
„ 9. The larva, its luminous organs magnified. 
„ 10. Some light cells and their tracheae magnified. 
