Vegetative Vigor of the Host as a Factor Influencing 



Susceptibility and Resistance to Certain Rust 



Diseases of the Higher Plants 



BY 



MORRIS ABEL RAINES 



A DISSERTATION SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIRE- 

 MENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY, IN THE FACULTY 

 OF PURE SCIENCE, COLUMBIA UNIVERSITY. 



Reprinted from the 



AMERICAN JOURNAL OF BOTANY, Vol. IX, No. 4, pp. 183-203, 

 April, 1922, and No. 5, pp. 215-238, May, 1922. 



