EFFECTS OF RADIUM RAYS ON PLANTS 995 



negative results were obtained with Ginkgo hiloba, Platanus sp., Fagus 

 sylvatica, and Tilia sp. Molisch suggested that the radium rays produced 

 these results by activating certain ferments or in favoring their production, 

 thus resulting m an activating of the nutrient materials. 



Gager (25) reported that the growth of corn {Zea Mays) was acceler- 

 ated by soaking the corn grains, before planting in soil, for 24 hr. in water 

 which had been exposed to radium rays for 26.5 hr. by suspending in it a 

 sealed glass tube containing radium bromide of 10,000 or 1,500,000 

 activity. The radicles of Lupinus albus were retarded in growth when 

 immersed in water previously exposed for 24 hr. to radium rays of 10,000 

 to 1,500,000 activity. Similar effects were produced by immersing the 

 radicles of Lupinus in freshly fallen rain water (which is known to be 

 radioactive) as contrasted with growth in rain water one month old. 

 The water in each experiment was caught by placing glass beakers in 

 the open during a rain. 



Stoklasa (77), however, reported that the radioactive water obtained 

 from Joachimsthal stimulated the growth of roots and shoots of Triticum 

 vulgare, Hordeum distichum, Vicia Faba, Pisum sativum, Lupinus angusti- 

 folius, Trifolium pratense, and Pisum arvense. Striking effects were 

 obtained in 8 hr. with barley (Hordeum). He also found that vegetative 

 processes are stimulated when 0.5 to 1.0 gm. of radioactive pitchblende 

 inclosed in glass is placed in jars containing growing plants. 



These results of Stoklasa were confirmed by Petit and Ancelin (62). 

 They obtained water charged with emanation to the desired degree by 

 keeping it in a fountain of radioactive cement, made by incorporating 

 concentrates of radium in the cement. Seeds of "ray grass," wheat, and 

 corn (Zea Mays) germinated much better in the radioactive water. 

 They report that the influence of the radioactivity begins to show itself 

 only after 12 days, on an average. 



In 1913 and 1914, Stoklasa (78) published a series of papers on the 

 significance of radioactivity in physiology. He reported that he and 

 his coworkers found that exposure to the emanation of 80 to 150 ME 

 promoted the metabolism of bacteria but retarded the reduction of 

 nitric acid to elementary nitrogen by the organisms concerned in that 

 process. When a mixture of yeast was exposed to emanation of 100 to 

 200 ME per liter of air, the absolute amount of the energy release of the 

 yeast cells was increased. Fermentation began earlier in nutrient media 

 containing yeast, and respiration was 70 to 110 per cent greater than 

 normal under conditions of exposure. These results are in harmony 

 with those reported by Gager (25). 



Seedlings grown in radioactive water of 70 ME had a dry weight 

 0.62 to 158 per cent greater than those grown in ordinary water for the 

 same length of time (Stoklasa, 78). Plants so exposed flower sooner and 

 produce more seed. An excessive amount of irradiation retards and 



