4o6 RESEARCHES ON FUNGI 



soon as the test-tube was plunged into the water the temperature 

 of the air within immediately began to rise and in the course of a 

 few minutes (certainly after 7 miinites) became equal to that of the 

 water in the beaker outside. 



The effect of the increased temperature on the fruit-bodies 

 quickly became obvious. After 3 minutes from the beginning 

 of the experiment the light emitted had become fainter ; after 

 4 minutes it had become very faint indeed ; and at the end of 

 7 minutes it ceased to be emitted, the gills becoming uniformly 

 non -luminous. 



Eleven minutes after the experiment was begun, tlie fruit-bodies 

 were taken out of the test-tube and allowed to cool in the air of the 

 dark-room. The emission of light was resumed but not until about 

 an hour after the cooling had begun, and even then it was very 

 feeble and irregular. Evidently the high temperature of 38° C. had 

 had an injurious effect upon the photogen. From this experiment 

 we may conclude that the maximum temperature for luminescence 

 in Panus stypt. luminescens is under 38° C. 



42° C. In an experiment similar to the last, but with the water 

 in the beaker at 42° C. instead of 38° C, the light emitted from the 

 fruit-bodies disappeared within three minutes. At the end of this 

 time the thermometer in the test-tube registered 39° C. After 

 4 minutes from the beginning of the experiment, the fruit-bodies were 

 removed from the hot air in the test-tube and cooled. Light from 

 the gills began to be emitted again about 5 minutes after cooling 

 had begun, but after 15 minutes was feeble relatively to that given 

 out by other fruit-bodies which were used for comparison. After 

 about an hour, however, the intensity of the light seemed to have 

 once more become normal. This experiment shows, therefore, that 

 the exposure of luminous fruit-bodies to a temperature of 39°-40° C. 

 causes the extinction of the light emitted in a very few minutes and 

 that, even when the exposure is very brief, the fruit-bodies are 

 injured so that they do not rapidly recover after being cooled. 



30° C. This experiment was conducted in the same manner as 

 the two which have just been described. After 15 minutes the 

 fruit-bodies were still glowing brightly, although perhaps not quite 

 so brightly as they had done at 22° C. After about 30 minutes 



