STUDIES IN THE EFFECT OP RÖNTGEN RAYS, ETC. 205 



jvrea fm' cfllijtiv.j exposure, nml this aix>ii will nnlj' jidmit i^bout 130 aMMls 

 swelled n,3 the result of steeping. 



Notice: — The following (ibbrcvint ions are used in this pnijcr for couvenience : " T\ib3 

 ctistnncc " menns the ilistanoe between the Rüulgen-rny tube-focus one! the object to be irrmlintoil, 

 "IrracUat«! mnteritil " means the seecla und jilnnts irmdinted. 



IiTa'iiitiou' ■wfts iimde by KotTi FujiN.VJrr at the R'nitgcn Labomtmy 

 of the Jiuitoudo Htispital in Toln-o. Tul» distance was 15-80 cm. Tlio 

 Il'Jiitgen tulje usixl was Gjba's water-cojl tube with a h;iv(hiess of Benoist 

 6°, and the current passhig through it was 10 milliainperes. To iiTadiato the 

 seeds, they werc placed flat in a iwrceLun dish (cuvette), and care was tiken 

 to UTadiato uuifoi'inly in turning the seeds over and over agmn and clmnging 

 their position as tha tulje was clwuged. 



ExPErj^fENT I. 



Tlie soeds were steeped iu water for 46 hours prior to the experimentä 

 an^ exposed to the rays of 40 H, 50 H, 60 H, 80 H, 100 H, 120 H, 150 H 

 when tlie water cjntent reached 57.49^, on Mirch 17, 1917. 21 houi-s affeir 

 irradiation they were sown on Mai'ch IS in the field, one grain for one stock, 

 the distance between the rows of field was 2 syaln? and the distance between 

 the plants was 1 syalcu. The \mt3r- was permitted to use Marquis Yositika 

 ToküGAWa's field at Fnjimi-Cho, Azabu, Tokyo, fo/ v/hich favour he expresses 

 his hearty tliauks. The field consisted of clay soil, and the former crops wore 

 Brassica campsstris L. var. (mikawasima-ua), Solanum mdomjena L. in 1915 

 and Arachis hypogxa L. in 1914. 



The manure given was 5 gr. of calcium superphosphate and ca. 140 gr. 

 of stable miuiure to each stock. 



The exjxjriment extended from Mavoli 19 to May 10, 1917. 



Ten seeds of each group were sown with the same number of uniiTadiatod 

 controls, surroiinded liy two extra rows iu the same distance of rows and 

 jjlant?. This cire was taken to minimize the special efiect of surroundings. 



The results of this experiment are tablated below. 



1. The writer expresses his henrty thaulc? to Jlr. Mat.todaiba for his kinllv help in the 

 irradi:ition. 



2. .•iyaJcu = O.ZOm. 



