PANUS STYPTICUS LUMINESCENS 401 



became visible at the end of about 20 seconds from the removal, 

 and was fairly bright at the end of 60 seconds. The fruit-body 

 was then placed on wet cotton wool in a damp-chamber. The next 

 evening it was found to be glowing with its fuU intensity. This 

 experiment, with slight variations, was repeated several times. 

 It thus appears that, under certain conditions, ether vapour 

 temporarily arrests the action of the photogen. 



A luminous fruit-body which was kept in the ether flask for 

 18 hours was found at the end of this time to be non-luminous 

 and to have lost its vitality. Long subjection to ether vapour 

 therefore seems to be fraught with fatal consequences. 



One cc. of chloroform was placed in the 250 cc. measuring flask 

 instead of ether, and a glowing fruit-body was inserted as before. 

 The light of the fungus rapidly diminished in intensity and, at the 

 end of 15 seconds, had entirely vanished. After 5 more seconds 

 the fungus was removed from the flask. Two seconds after this 

 removal, the light of the gills began to return ; the glow then 

 brightened but soon began ta grow dim again ; and within one or 

 two minutes of the removal became entirely invisible. This ex- 

 periment was repeated with another fruit-body with the same result. 

 These fruit-bodies were placed in a damp-chamber but they did 

 not recover their luminosity, and next day they were found to be 

 dead. It is evident therefore that 1 cc. of chloroform in a 250 cc. 

 flask is much more fatal to a fruit-body than I cc. of ether. 



Effect of Temperature. — The range of temperature required for 

 the emission of light was determined by means of the following 

 experiments. 



0° C. To subject luminous fruit-bodies to a temperature of 

 0° C, an ice-bath was employed in the manner indicated by Fig. 173. 

 Two luminous fruit-bodies were placed in a test-tube (a) containing 

 a thermometer held in position by means of a folded rubber band 

 and cotton wool. A large block of ice (a part only shown at c) 

 was then taken into the laboratory and a deep cavity made in it. 

 This cavity was filled with ice-water (b). The test-tube containing 

 the fruit-bodies and thermometer was then pushed down into the 

 ice-water and covered with an inverted beaker (d) lined with cotton 

 wool. The block of ice and the beaker were then covered over 



VOL. III. - ^ 



