PLATE 2 



HISTOLOGICAL EFFECTS OF RADIUM RAYS ON LUPINUS ALBUS 



AND PHASEOLUS VULGARIS 



PAGE. 



Fig. A. L. albus. Cross-section taken through a fibro- vascular bundle 

 of the hypocotyl of a seedling grown from a seed exposed for 6 

 days, during imbibition of water in moist sphagnum, to rays from 

 a Lieber's radium-coated rod of 25,000 activity. Experiment 16 . 225 



B. L. albus. Cross-section through a fibro-vascular bundle of 

 the hypocotyl of a seedling from an unexposed seed, but of the 

 same age as that of A, and grown in moist sphagnum . . .225 



C. L. albus. Cross-section taken through the tap-root of the 

 seedling from which A was taken ...... 226 



D. L. albus. Cross-section taken through the tap-root of the 

 seedling from which B was taken . . . . . - . 226 



E. P. vulgaris. Cross-section through the hypocotyl of a seed- 

 ling from a seed exposed, during imbibition and germination in 

 moist sphagnum, to rays from a coated rod of 10,000 activity. 

 Experiment 15 . . . . . . . . . . 226 



F. P. vulgaris. Cross-section through the hypocotyl of a seed- 

 ling of the same age as E, and also grown in moist sphagnum, 



but from a seed not exposed to radium rays .... 226 



