IOO 



PHYSIOLOGY OF NUTRITION 



p IG 6 4- — Wheat plants grown in extract of toxic soil. I and 2, undiluted extract; 3 and 

 4, equal parts of extract and distilled water; 5 and 6, one part extract diluted with nine parts 

 of distilled water. (After Schreiner and Shorey. Reproduced by permission of U. S. Dept. 

 Agric, 1909.) 



Fig. 65. — Vicia faba (Windsor bean) plants grown in water extract of bog-soil and in bog 

 water. 1, extract; 2, bog water; 4, bog water neutralized with calcium carbonate; 5, bog 

 water treated with carbon-black and filtered. (After Dachnowski.) 





