266 



HIDEO KOMUKO. 



Table I. 



Control : — Of 10 seeds 8 developed into plants about 20 cm. in length. 



As Fig. 1 sLows, tlio irradiated seeds, wlioso sprout did not appear on 

 the surface of the soil, germinated, aud, moreover, they were of almost tha 

 same size aud most of them ^vere dead, but of the rather sti'ongly irradiated 

 ones many remained. Tlie middle of 150 H-seedling3 in Fig. 1 remained 

 healthy up to the end of the esj^eiiment (May 10). It is proved by the 

 aftermeutioned culture aud germination experiments that seeds containing 

 more tlian 50^ water, ^\•heu the dose of X-rays exceeds a certain Hmit, will Ix; 

 afTected only to an injm-ious stimulation. That many strongly ÜTadiated seeds 

 remain, may lie due to the fact, according to the writer's supposition, that the 

 sti'ongly irradiated take a much longer time to develop to a state where the 

 growth ceases, the weakly iiT.idiattd may reach this state sooner tliau the 

 former. 



EXPERIHIENT II. 



In the second experiment, the writer modified the mode of cultivation aud 

 used a diflerent kind of soil. S^^ecial wooden fi'ames were made instead of 

 large jx)ts, which were 6 syciku long, 1 sijahu wide and 1 syaliu high. 



5 of these frames were placed on the ground and the same quantity of 

 humus was filled in each. Seven kradiated seeds wliieh came fi-om the same batch 

 used for the first experiment wei« used. Thoy were sown with controls on a 

 straight line in the middle of the fi'amo, with intervals of 5 sun^ and tsvo 



1. sun = 3.03 cm. 



