Eig. 9. Photograph showing the action of arsenious acid on barley in the presence 

 of nutrient salts. (March 16th May 9th, 1911.) 



1. 



2*. 



2. 



3. 



4. 



5. 



6. 



7. 



8. 



9. 

 10. 

 11. 



Control. 



1/50,000 



1/100,000 



1/150,000 



1/200,000 



1/250,000 



1/500,000 



1/1,000,000 



1/5,000,000 



1/10,000,000 



1/25,000,000 



1/50,000,000 



arsenious acid. 



