.STUDIES IN THE EFFECT OF RÖNTGEN RAYS, ETC. 291 



EXFL.\N.VnON OF PL-VIES. 

 PL ATE XI. 



Fig. I. Sceils of " Sengoltu-kurome " were steeped iu water for 46 hours (when the water oon- 

 tcnta reached 57.49%) and exposed to rays ou March 17, 1917. On the next day they were sown 

 21 hours after irradiation in Slarqiiis Tokuo.\wa"3 field at Aziibu, Töky5. The figure shows 

 the cjnditions at the end of the experiments on May 10. 



(Of ten seeds of each lot these are the remainder of Ihe seedlings, while the rest were 

 found decayed or altogether missing.) 



Fig. 2. Seven seeds, from the batch of Exijeriment I, were sown 17 hours after irradiation 

 in the soil of large wooden frames and 7 sun pots. The picture represents their condition at the end 

 of the experiments on May 22, 1917 (these are the remaining seedlings, from seven of each lot.) 



Fig. 3 and 4. After 31 hours steeping, the seeds of " Sengolcu-kurome " were irradiated, their 

 water contents reaching 50%, on March 31, 1917. They were sown, on April 1, 17 hours after 

 irradiation in the field of our institute. Photographed on May 1. They are shown standing in 

 the field. 



Fig. 5. Conditions of plants of each lot from Figs. 3 and 4 at the end experiment, June Ifi. 



Fig. 6. Seedlings which were \ised for the culture in Knop's solution. Two seeds, from 

 the batch of Experiment m, were sown in s,aw-dust on AprU 2. On April 9 they were put 

 into Kxop's solution and photographed on .\pril 16. The seedlings of 50 H (due to injury) and 

 80 H up did not develop further than this stage. 



Fig. 7. Condition of the above water-cultured plants 22 days after treatment, on May 1, A 

 black point of a 30 H- plant which exists at the lower part of a shoot was caused by injury. 

 Therefore, the growth is inferior to that of the others. 



Fig. 8. Condition at the end of experiments, on June 16, of the plants of Fig. 6. 



Fig. 9. Plants grown from the seeds of " Hyogo " which were steeped for 24 hours before 

 irradiation when the water content reached 57.32% irradiated ou Oct. 28, '17 nnd sown the next 

 day. State on June 22 at the end of experiments. 



PL.iTE XII. 



Fig. 10. Fruits from the above plants. These plants of Experiment V were seriously 

 damaged by I'ipistrilhts ahramus. The number shown on some plants and fruits of 20 H 

 coincides in two figures ; they are the number of individuals in the field. 



Fig. 11. Plants grown from seeds of " Hyogo " which were steeped 34 hours before irra- 

 diation (when the water content reached 63,37%) and irradiated on Oct. 28, '17. On the next 

 day they were sown, 22 hours after irradiation, in the field o£ our institute (the field for 

 Experiment III). State at the end of experiment, June 22, '18. 



These plants of Experiment VI were also severely damaged by PipistrlUus abramiis. 



