Shining Fish, Flesh, and Wood 501 



obviously the result of processes occurring in a living plant. A. 

 Raffenau-Delile (1833) examined the phosphorescence of the com- 

 mon luminous mushroom of olive trees, Agaricus olearius, and 

 Tulasne (1848) wrote his long paper on the spontaneous light of 

 rhizomorphs, dead leaves, and the olive-tree agaric. 



A more modern experimental approach to determine the cause 

 of fungal light was made by J. H. Fabre (1855) . Following a sug- 

 gestion of Tulasne, that it would be important to know whether 

 more oxygen was absorbed and more CO2 and heat produced in 

 luminous than in non-luminous parts of a fungus, Fabre measured 

 these gases and found that the luminous pileus of Agaricus olearius 

 did produce more CO2 than the non-luminous fungal regions. How- 

 ever, he could detect no rise in temperature. In the last third of 

 the century the identity of fungus light and that of wood became 

 universally accepted. The principal student was Friedrich Ludwig 

 (1851-1918), Oberlehrer at the gymnasium in Greiz, whose inaug- 

 ural dissertation was entitled " Ueber die Phosphorescence der Pilze 

 und des Holzes " (Gottingen, 1874) . 



Shining Flesh and Animalcules 



In the meantime, ideas on phosphorescence of the sea underwent 

 a reversal. The old theory that diffuse sea light was due to decom- 

 position of organic material gave way to the universally accepted 

 belief that all sea light came from microscopic organisms. It was 

 logical to hold that the light of dead fish must also be clue to micro- 

 organisms, as Henry Baker had suggested in 1742. 



For example, John Murray (1821) in his treatise, " on the Lumi- 

 nosity of the Sea," and in his book, Experimental Researches (1826: 

 72) referred to whiting and mackerel which " yield light in the 

 incipient stage of decay. In this case I am of opinion that it pro- 

 ceeds from adhering, perhaps parasitic, luminous animalculae, the 

 evolution of light being the effect of the slight increment of tempera- 

 ture produced by the commencement of animal decomposition." 

 Michaelis (1830) and Ehrenberg (1834) quite naturally thought 

 of animalcules as causing the luminescence of fish as well as phospho- 

 rescence of the sea. 



In 1838 D. and R. Cooper published in a medical journal an 

 important but overlooked paper on the light of human cadavers, 

 which came very near the truth, although these observers finally 

 interpreted the luminescence they observed to be due to " a peculiar 

 state of decomposition." 



The chief source for the Coopers' study ^vas a human corpse, 



