264: HIDEO KOMCKO. 



the iiTacliatecl seeds of Vicia /aha, there was no diöeronce iu the condition of 

 cells compared with the couti'ol in weak iiTadiatiou ; with a certain dose, there 

 were rather mauv division figures, but after strong iiTadiation mitoses are very 

 seldom met with and almost aU cases were anomalous, the chromosomes having 

 became slender or fragTaentary and were scattered in the cytoplasm, and, more- 

 over, the initotic figm-e of anaphase and teloj)hase was A'ery rare and occasionally 

 iiTegiilar. After a certain dose, the chromosomes became short and thick, the 

 unclear membrane somewhat in'egular, and the chromatic substance increased 

 or decreased very much. In other casas, changes were seen, such as multi- 

 nucleated cells and others, resembKng those of tumor cells. 



9. From tlie cytological observation of yoimg plants of Vk-ia /aba 

 iiTadiated with 200 H, the ceU and nucleai' division were entirely inteiTupted 

 and the i^eriphery of nuclei desti'oyed, some in karyolytic condition and others 

 in karyon-hexis. 



III. Culture Experiments. 



It was the wish of the ■WTiter to show by Experiments I-IV that an 

 im]^iediment of gi-owth ^nU occur with any of the doses given. E. Schwarz 

 (1913) observed the apparent impediment by :roH on the seeds in a resting 

 state (air-dried sesds) of Victa/aba. M. Koernicke (1915) denied this and 

 said that in aii'-dried seeds of Vicia faba tha impediment appeai'ed first at 

 above 50 H, moreover, he repoi-ted that seeds on which the tip of the 

 radicle appeared after m;my days steeping were severely impeded iu their 

 gi-owth by 10X( = 5 H) and 15X( = 7.5 H). 



G. Schwarz (1907) studied the relation between the sensibility to Röntgen 

 rays and the water content of seeds, and said that the sensibility to Röntgen 

 rays is proportional to the dcgi-ee of the water content of irradiated cells, so 

 the writer steeped the seeds iu water for different lengths of time and determined 

 their water content. 



The seeds iised for these experiments were " Sengokn-kurome ", a race of 

 Vicia /aha obtained fi-om the Tokyo Konoen, the air-dried ^veight of ^\h-cli 

 was 0.9 gr. 



It was the gi-eat regi'et of Üie writer that he could not use more than 20 

 seeds for each dose, because the Röntgen tuba iBed permitted only ca. ;rlO- cm. 



