Bulletin No. 18. v. P. P.-68. 



U. S. DEPARTMENT OF AGRICULTURE. 



DIVISION OF VEGETABLE PHYSIOLOGY AND PATHOLOGY. 



B. T. GALLOWAY, CHIEF. 



THE 



PHYSIOLOGICAL ROLE OF MINERAL NUTRIENTS. 



BY 



OSCAR LOEW, 



OF THK 



Divisiofi of Vegetable Physiology and Pathology 



. WASHINGTON: 



GOVERNMENT PRINTING OFFICE. 

 1899. 



