STUDIES IN THE rFFFCT OF RONTGtN RAYS, ETC. 



2(31 



Casimir exposed the seefUings of Vicia/ahi to tlio rays of 20011 jukI 

 inve'stipitcd cytologiciiUj-. Accordiuj^ to the clescriptitHi of J. Wetteker/ 

 Casmir's result wag 113 follows : — " Als Resultiit dor Bestraliluuf; ergab sicli, 

 (Liß iu dem Keiiuliug die Zell- iiud Kerutciliuig völlig zum Stillstand geLwigt 

 war. Am deutliclisten ti'atou Zerfiillsersdlicinungen am Zellkcru auf, l)e3tehend 

 in Kjtrjorliexis und lüiryolysis. Die enorme Dosis liatta so jjrompt auf die 

 leblmft proliferierenden ZeUeu der Keimlinge gemrkt, di^J^ der Kemteiluugs- 

 prozess sofort inliibiert war ". 



TLe WTiter (1916) made a cytological investigation on Vicia fain exposed 

 t ) tlie rays of 5 H, 10 H, 20 H, 40 H, CO JI juid 80 H. The results obtjiined 

 were as follows : in the preparations of 5H-20H, there appeju'ed no düTerence 

 compared with the control, iu the 40 H preparations, more mitotic figures were 

 found tlian in the case of othere, and the chromosomes seemed to become 

 somewhat tliick and sliort compared with the C3ntiol, Trat there was no change 

 iu the division figures, and the stage of auaphase and telophase were found 

 fi'equently iu each preparation, aud in the preparations of 80 H the nuclei 

 were more or less degenerated, the outline of the nuclear membrane being scarcely 

 visible. In such cells, the cytopksm was filled with large vacuoles. The 

 starch grains in the root cap (smd the lower part of thi3 periblem) were fouud 

 to have changed in size and were more scattered iu the cell. The wi-iter 

 o1jser\-ed tluit the chromosomes assumed an irregular arrangement aud became 

 more or loss slender in the metixpliase, aud the stage of auaphase and telophase 

 were very rare and w^ere foiuid in an abnormal state. 



Yam ADA (1917) reported the results of the culture-experiment on Onjza 

 sativa exposed to the rays. He used " Takenari ", an aquatic race of Onjza 

 saliva, for his exjoeriments aud irradiated them as follows : — • 



1. Wetteher, J. Handbuch der Röntgentherapie, 1. Bd. pp. 299-300. 



