Fig. 9.—Spectra of various luminous animals (after McDermott). 1. Portion of the visible solar (grating) spectrum showing Fraunhofer lines. 2. Pyrophorus noctilucus (Langley and Very.) 3. Lampyris noctiluca (Conroy). 4. Photinus pyralis (Ives and Coblentz). 5. Photinus consanguineus (Coblentz). 6. Photuris pennsylvanica (Coblentz). 7. Phengodes laticollis (McDermott). 8. Bacterium phosphoreum, B. phosphorescens or Bacillus photogenus (Molish). 9. Photobacterium indicum (Barnard). 10. Mycelium X (Molish). 11. Luminous bacteria (Förster). 12. Agaricus sp.? (Ludwig). 13. Fluorescent spectrum of luciferesceine of Photinus pyralis (Coblentz). Only the extreme ends of the bands are shown and no attempt is made to indicate the relative density of different portions of the spectra.
Table 5.—Limits of Spectra of Various Luminous Organisms
| Light | Spectrum (µ) | Emission maximum | Observer | Method and remarks |
|---|---|---|---|---|
| Cypridina hilgendorfii | 0.610-0.415 | Harvey, 1919 | Eye observation, Zeiss comparison spectroscope. | |
| Chætopterus insignis | 0.55-0.44 (approximately) | Lancaster, 1868 | Eye observation. | |
| Pyrophorus noctilucus | 0.72-0.486 | Dubois, 1886 | Eye observation. | |
| Pyrophorus noctilucus (thoracic light) | .640 - .468 | 0.57 | Langley and Very, 1890 | Eye observation and comparison with solar spectrum of equal intensity. |
| Pyrophorus noctilucus (abdominal light) | .663 - .463 | |||
| Photinus pyralis | .67 - .51 | .552 | Ives and Coblentz, 1909 | Photographic comparison with carbon glow lamp of equal intensity. |
| Photuris pennsylvanica | .59 - .51 | Coblentz, 1912 | Photographic comparison with carbon glow lamp of equal intensity. | |
| Photinus consanguineus | .65 - .52 | .578 | Coblentz, 1912 | Photographic comparison with carbon glow lamp of equal intensity. |
| Phengodes laticollis | .65 - .52 | McDermott, 1911 e | Eye observation. | |
| Lampyris (glow worm) | .656- .518 | Conroy, 1910 | Eye observation. | |
| Photinus | .670- .487 | Young, 1870 | Eye observation direct vision spectroscope. | |
| Bacteria | G to F extending toward D for long exposure | Barnard, 1902 | Photographic. | |
| Bacteria | Somewhat beyond G to D | Fisher, 1888 | Eye observation. | |
| Bacteria | .58 - .43 | Förster, 1887 | Eye observation Zeiss. Abbe microspectral ocular. | |
| Bacteria | >.500 to .350 | Bright band at .4 | Forsyth, 1910 | Photographic, quartz spectroscope. |
| Agarious melleus | 0.56-0.48 (approximately) | Ludwig, 1884 | Eye observation, Sorby Brown microspectroscope. | |
| Xylaria hypoxylon | .54 - .46 (approximately) | Ludwig, 1884 | Eye observation, Sorby Brown microspectroscope. | |
| Micrococcus Pflugeri | b into the violet | Ludwig, 1884 | Eye observation, Sorby Brown microspectroscope. | |
| Mycelium X | .570 - .480 | Molish, 1904, book | Eye observation, Zeiss comparison spectroscope. | |
| Bacterium phosphoreum | .570 - .450 | Molish, 1904, book | Eye observation, Zeiss comparison spectroscope. | |
| Bacterium phosphorescens | .570 - .450 | Molish, 1904, book | Eye observation, Zeiss comparison spectroscope. | |
| Bacillus photogenes | .570 - .450 | Molish, 1904, book | Eye observation, Zeiss comparison spectroscope. | |
| Pseudomonas lucifera | .570 - .450 | Molish, 1904, book | Eye observation, Zeiss comparison spectroscope. |
As first shown by Dubois (1886) for Pyrophorus, and confirmed by myself for Cypridina, the light is not polarized in any way. I may add that the Cypridina light like any other light may be polarized by passing through a Nicol prism.
Several writers [Dubois (1914 book)], Fischer (1888), Molisch (1904 book) have noticed that the light of luminous bacteria changes in color if grown on different culture media. Light which is "silver white" on dead fish becomes "greenish" on salt-peptone-gelatin media and more yellow on salt-poor media. Peron (1804) and Panceri (1872) describe the light of Pyrosoma as yellow to greenish after death of the animal and reddish on stimulation; then fading out through orange, yellow, greenish and azure blue. Polimanti (1911) describes the normal light of Pyrosoma as greenish, and states that as the animals die, or if they are kept at temperatures above the optimum, the light becomes more red. McDermott (1911, b) noticed that the light of fireflies placed in liquid air became decidedly reddish just before going out and on rewarming the first light to appear was reddish followed by the proper shade at higher temperatures. I have frequently observed
a more reddish color from luminous tissues of the firefly upon the addition of coagulants such as alcohol, and have noted that the light of Cypridina becomes weaker and more yellow at both low (0°) and high (50°) temperatures. The meaning of these color changes will be discussed in [Chapter VII].