Acknowledgements 



The experimental work herein reported was made possible by a 

 research grant from the Brown Company, Berlin, New Hampshire. 

 The planning and supervision of the project was the responsibility 

 of a supervisory committee consisting of the following: L. T. 

 Kardos, Agronomy Department, Chairman; Stuart Dunn, Botany 

 Department; L. P. Latimer, Horticulture Department; Lewis Swain, 

 Forestry Department; G. P. Percival, Agricultural and Biological 

 Chemistry Department; and Edward Katz, Bacteriology Depart- 

 ment. Most of the work of caring for greenhouse cultures of plants 

 and field plots was done by L. P. Wolfe, Jr., and W. A. MacDonald. 



