90 INTRODUCTION TO THE STUDY OF FUNGI 



sufficiently powerful to enable the time on a watch to be seen 

 by it. The effect produced by it upon the traveller, when on 

 a dark night he comes suddenly upon it glowing in the woods, 

 is startling ; for to a person unacquainted with this phenomenon 

 the pale, livid, and deadly light emanating from it conveys to 

 him an impression of something supernatural, and often causes 

 no little degree of terror in weak minds or in those willing to 

 believe in supernatural agencies. The kind of light emitted in 

 all cases is described as shining with a pale, livid, and greenish 

 phosphorescent glow. 1 This luminosity is not confined to the 

 Agarics, but may be witnessed in those cord-like Ehizomorphs 

 which run through rotten wood or bark, and are common in 

 mines. The thin mycelium which traverses rotten wood in 

 every direction, under favourable conditions exhibits the same 

 peculiarity. Eecent observations have determined that in 

 some cases luminosity is produced by species of bacteria. 

 Yet, under all these conditions and manifestations, the cause 

 of the light is still as much of a mystery as ever, despite 

 all suggestions as to its originating in some connection with 

 phosphoric acid. 



This is merely a chapter of hints and suggestions which 

 might have been considerably extended, but it will be recog- 

 nised that in many cases there is no satisfactory explanation at 

 present to be given for the phenomena alluded to. There is 

 still ample work for the chemist, but it is not remunerative, 

 and in many instances necessarily one of much labour and 

 assiduity. Fungi are themselves so putrescent that their 

 examination must be commenced at once, when they are col- 

 lected ; besides, it is not always that a sufficient supply for 

 investigation can be obtained at one time. When we learn 

 that 50 lbs. of Agarics are required to obtain a quarter of an 

 ounce of muscarine, and that the same quantity of Boletus 

 luridus is necessary to obtain from it any alkaloid it may 

 possess, or discover truly the source of the blue colour, we are 

 not sanguine as to much advance in this direction. 



1 Bomcmce of Low Life amongst Plants, by M. C. Cooke, London (1893), 

 p. 208. 



