56 Effect of Arsenic Compounds 



of 1/1,000,000, but fix)m this point down to 1/250,000,000 a constant 

 depression showed itself, which was paralleled by a similar depression in 



gin. 

 1-4 



1-2 

 I'O 



•e 

 ■e 



•4 

 ■2 

 





TbfoJ 



, Shoot 



Root 



10 e-e 



2 I -2 



l» 1: 1,000,000 



■I -04 -02 



Fig. 12. Curve showing the mean value of the dry vreights of ten series of barley plants 

 grown in the presence of arsenio acid and nutrient salts. (Feb. 28th — ^April 24th, 

 1911.) 



1-6 



1-4 

 12 

 10 

 •8 



40 20 10 



I -4. a 



l'|:|0,000,000 



■06 -05 '04 



ToW 



3hoo> 



Root- 



Fig. 13. Curve showing the mean value of the dry weights of ten series of barley 

 plants grown in the presence of sodium arsenite and nutrient salts. (Feb. 10th — 

 April 18th, 1913.) 



the sodium arsenite series from 1/25,000,000 to 1/250,000,000, the curves 

 grading downwards instead of up towards the normal. With peas sodium 



