390 RESEARCHES ON FUNGI 



for eleven hours. In other experiments smaller photographs were 

 made with four fruit-bodies only ; and, no doubt, if one so desired, 

 very small photographs could be made with the light of a single 

 fruit-body. Exposure of the plates for two hours gave good results, 

 but shorter exposures than this were not attempted. 



The Emission of Light by the Mycelium.— Some of the Panus 

 fruit-bodies sent to me by my North American correspondents 



Fig. 169. — A shadow-photograph of a black-paper star made 

 with tlie light of about twelve fruit-bodies of Panus 

 stypticus p. f. luminescens gathered at Saint Paul, Minn., 

 U.S.A. The black circle at the periphery was caused 

 by the base of an inverted crystallising dish. Exposure 

 11 hours. Reproduced the original size. 



were attached to pieces of wood which had been broken away from 

 stumps, logs, etc. This material was moistened by placing it on 

 wet cotton wool. After some hours or days I observed that not 

 only did the fruit-bodies emit light but, in some instances, also the 

 mycelium at the broken surface of the wood. Sometimes, however, 

 pieces of wood bearing fruit-bodies never showed the least sign of 

 luminescence. To settle the question of the luminosity of the 

 mycelium I therefore resorted to the method of pure cultures. I 

 placed a fruit-body on a sterilised glass slide and soon obtained 



