486 History of Luminescence 



brilliant points. The odor was strong like a sponge. On succeeding 

 nights the light became weaker and disappeared on January 10, 

 but the color and odor remained. The letter concludes with this 

 sentence: " Si je ne m'abuse pas, ce fait est tres singulier, et merite 

 quelque attention de la part des physiciens." 



Roots of the European blood root, Potentilla tormentilla (Anon., 

 1795) , as well as Valeriana (K. von Kortum, 1800) and garden let- 

 tuce roots (Anon., 1832) sometimes luminesce. There are also 

 records of luminous melons,^* and, according to Heinrich (1815: 

 337) , of cabbages and beets, tubers, bulbs, and berries; likewise 

 peaches, which may luminesce as they begin to rot (J. A. Deslon- 

 champs, 1838) , and dead oak leaves on the ground in damp woods 

 (Naudin, 1846; L. R. Tulasne, 1848) . The luminescence of living 

 leaves has also been seen (C. von Szutz, 1800) .^^ It has even been 

 reported by F. Goebel (1824) that luminous bubbles of carbon 

 dioxide form during fermentation of raspberry juice and arrak. He 

 thought the effect might be electrical, owing to rubbing of the glass 

 surface by the gas bubbles. In later trials he never saw the light 

 again. 



Many unusual cases of luminescence were collected and discussed 

 in an article (1808) of Sigismund Friedrich Hermbstadt (1760- 

 1833) , a " Sanitatsrath " in Berlin, on the light of organic bodies 

 while alive and after death. In addition to human sweat, eggs, 

 potatoes, roots, etc., already mentioned, Hermbstadt declared that 

 he had seen luminous " faulendem Kase," without giving further 

 details. The light of cheese is undoubtedly bacterial or fungal in 

 origin, but information on the organism responsible is lacking, and 

 no recent cases of luminous cheese appear to have been recorded. 



The light of unusual vegetable materials such as potatoes and 

 roots was so rare that practically no experiments were attempted; 

 and little more than a record of the phenomenon is to be found. 

 On the other hand, shining wood was common and served as ma- 

 terial for extensive experimental research in the 1780's and 1790's, 

 chiefly in connection with the effect of gases. 



»* Casati, De igne, 349, Francofurti, 1688. 



^^ The origin of the bluish-green " Phosphorlicht," observed between 9 and 10 p. m. 

 one evening in September, 1800, on the leaves of a garden plant, Phytolacca decandra 

 (Linn) , by Carl von Szutz, an apothecary of Hungary, is uncertain. Szutz picked the 

 leaves and the light continued to shine, sometimes yellowish-green, sometimes bluish, 

 sometimes stronger, sometimes weaker, depending on whether the " Zug der Luft " 

 was stronger or weaker. The phosphorescence lasted until after midnight and then 

 disappeared. The light may have been an electrical phenomenon, although luminous 

 fungi growing on living leaves is a second possibility. 



