ROENTGEN RAYS 171 



proportions, acting in conjunction with certain nutrient 

 substances. 



Among the hydro-carbons, glucose enables copper salts 

 to exercise their peculiar property to the greatest extent. 

 Germination is not affected by salts of copper. Penicillium 

 glaucum was the fungus used for the experiments. 



Renard, Jourii. de Bot.^ 1902, p. 97. 



BECQUEREL'S RAYS ( = Radium rays) 



Dauphin has experimented with these rays on Mortier- 

 ella, and finds that they arrest the growth of the mycelium, 

 and prevent the germinatiou of spores. These are not 

 killed but simply paralysed or rendered latent, and germi- 

 nate or continue growth when placed under normal con- 

 ditions. Cysts are formed in the interior of the cells of 

 the mycelium, which are obviously protective bodies pro- 

 duced under the exceptional conditions. 



Dauphin, Compt. Rend., 138, p. 154 (1904). 



ROENTGEN RAYS 



Koernicke finds that these rays inhibit the growth of 

 fungi after prolonged action. 



Koernicke, Ber. d. deutsch. Bot. Ges., 1904, pp. 22 and 

 148. 



