Dr. Dennis R. Hoagland, Pro- 

 fessor of Plant Nutrition, University 

 of California, Berkeley. Mineral nutri- 

 tion of plants; Relation of plants to the 

 soil. 



Dr. H. H. Dixon, Professor of 

 Botany, Trinity College, Dublin, 

 Ireland. Transpiration and the ascent 

 of sap. 



