22 AKT. 3. — SEIICHI kawamüba: 



The fading of light takes place also uniformly over the gills ; all 

 the parts becoming non-luminous at the same time. 



Delile 15 observed that Pleurotus oleareus D. C. was luminous 

 only at night. Akcangeli 2) contradicted this statement, maintaining 

 that the fungus is luminous in the day-time also. It was fitly 

 remarked by him that, in order to ascertain that fact, the speci- 

 mens should be observed in a dark room, the observer waiting 

 from three to ten minutes until when the eye shall have sufficiently 

 recovered the sensibility to recognize the fungus-light in the dark. 

 The results of my repeated experiments on Pleurotus japonlcus go 

 to confirm Aecangeli's view in the main. I have found that the 

 time required for bringing our eyes into proper accommodation to 

 see the light in the dark varies considerably according to indi- 

 viduals and also to the state of weather. Whereas in rainy or 

 cloudy day it may take, after entering the dark room, only a 

 minute or thereabout to be able to recognize the luminous fungus 

 placed in it, on bright sun-shiny days it may require from three 

 to seven minutes to arrive at the same end. The reason is 

 obvious. Further experiments have shown that, while some person 

 could exactly tell the number and position of the fungi in one 

 minute, others who have entered the dark room at the same time 

 required three minutes to come to the recognition. 



It might be asked if the fungus does not emit light in the 

 day-light, but does so only on being placed in a dark room as on 

 a dark night ; in other words, if the presence or absence of sun- 

 light have any direct influence on the luminosity of the fungus. 

 To determine as far as possible the point in question, I have kept 

 a specimen of the fungus in the dark room for a long time before 

 I entered ; it took several minutes before I could recognize the 



lj Delile, Nouv. exam. de la phospk. de l'Ag. de l'Olivier.— 2) Arcangeli, G., Eicerche bulla 

 Fosforescenza del Pleurotus oleareus D.C., 1889, 



