284 HIDEO KOilURO. 



They -were pliotograpliecl immediately after examination, and tben wrapped 

 into wet paper in a 1x)x (for carrying). 30 minutes after again planted in 

 the sands and their growth observed. The gi-owth of 7 H- and 10 H- plants 

 was better compared to the controls and the 15 H, but the \mter could not 

 measure theii' lengths, for rats damaged them all the night before the measui-e- 

 ment. By this fact, it is supposed that 15 H may not cause a good stimula- 

 tion in this case. 



KoERNlCKE states that the effects of X-rays n^wu Ficia /aba difier 

 ftccording to their race. In the steeped irradiated seeds of " Sengoku-km'ome," 

 as iiforesaid, 20 H-plants wove liest in growth and maximum in dry-weight 

 compared with the controls and the other iiradiated ones. These two results 

 (Experiment III and IX) seem to contradict each other, but they can 

 bo explained by Koekxicke's results or by the difference of environmental 

 conditions. 



Experiment X. 



Seeds of " Wase-soramame," which had Ijeen stee^xjd in water for a few 

 days, so that the tips of the radicles appeared fi'om the seed coat, were exposed 

 to the rays for one hom- and then sown in sands, one hour after irradiation, 

 on AprU 27, 1922. 



Half of them developed a little, the other half sprouted and the young 

 shoots and roots reached ±1.5 -3.0 cm. 



The X-ray bulb used for this experiment was Okur.\'s water-cool tulje 

 after Müller, the hardness of which was ±10.5'' "Wehxelt. Spark length 

 was 15 cm. and the tnlte cim-ent ±2.5 milUampsres. Tube distauco 30 cm. 

 The writer made the iiTadiation under tho direct conti'ol of Dr. N. Fuji at 

 the Röntgen laboratory of the Agricultural Ex^Deriment Station, Department of 

 Agricidtm-e and Commerce, Nisigahara, Tokyo. 



A water cell was inseiicd between tho bull) and the seeds. The coll is 

 made of two aluminium disks 0.3 mm. thick sup^wrted by brass rings of 1 cm. 

 height and provided with two short brass tubes for the in- and outflow of 

 water. This device was used to jirevent tlic thermal factor enteiing into the ex- 

 perimentation. 10 minutes' oxposm-c corresponds to 8 H of Holzkxecht's unit. 



