118 History of Luminescence 



nous mollusc] shine like lightning? " Buonanni quoted Kircher's 

 " Mundus subterraneus " in which he observed a " fiery rain, spar- 

 kling in the darkness and a shining light similar to that of glow- 

 worms," and then stated that this light was not present merely on 

 balani but was to be found in many marine and land animals, in 

 shellfish, worms, Crustacea, sea lungs (medusae) , dead fish, the 

 tongue of the lantern fish, mushrooms, eyes, hair, etc. 



Buonanni was particularly impressed with putrefaction as the 

 cause of light, a theory originally attributed to Aristotle " who 

 thought there was no marine light without putrefaction." ^^ In addi- 

 tion Galenus *° had seen a light from rotten pigeon excrement and 

 Esichius [Hesychius] held that glowworms were born in tows and 

 thickets after a previous putrefaction. Buonanni repeated Bartho- 

 lin's argument against the view, that " if putrefaction were really 

 the cause of the light we should expect to see light arising from the 

 skin of hogs covered by dirt, and furthermore how could such a 

 noble thing as light be produced by such a low and vulgar thing as 

 putrefaction? " Putrefaction could not be thought of as producing 

 the light, but might liberate the various principles which make up 

 the organisms, thus freeing the light particles previously combined 

 in complex substances. 



However, Buonanni pointed out that the light of balani could 

 not be explained in this way as they lighted before putrefaction. He 

 also disposed of the idea that the light was similar to the sparkles 

 observed when a horse is curried, since they lighted without rub- 

 bing. He concluded that balani are able to produce nitrous and sul- 

 furous vapors because they generate a mineral odor similar to burn- 

 ing horn. When taken from the cold water of the sea into the heat 

 of the air, these vapors burn and shine in a manner quite similar 

 to the vapors over buried corpses in cemetaries, called will-o-the- 

 wisp. Certainly such speculations were well suited to arouse the 

 interest of the general reader. 



^^ The author has been unable to find a statement to this effect in Aristotle's works. 

 There is considerable discussion of the sea and of putrefaction in Metereologia, but 

 only the statement (Book II, Sec. 1) : " the sea putrefies quickly when broken into 

 parts but not as a whole; and all other waters likewise. Animals too are generated in 

 putrefying bodies, because the heat that has been secreted, being natural, organizes 

 the particles secreted with it." Many later writers took pains to emphasize that lumi- 

 nescence of fish occurs before putrefaction sets in. 



^^ In David Brewster's (1787-1868) Letters on natural magic addressed to Sir Walter 

 Scott, Bart (1831, letter 13) , discussing heat and combustion produced by fermenta- 

 tion in moist hay stacks, we find: " Galen informs us that the dung of a pigeon is 

 sufficient to set fire to a house, and he assures us that he has often seen it take fire 

 when it had become rotten. Casati likewise relates, on good authority, that the fire 

 which consumed the great Church of Pisa was occasioned by the dung of pigeons that 

 for centuries built their nests under its roof." 



