CONTENTS 
PAGE 
iNTROnUCTION ......... 5 
History .......... 5 
Problem and Method of Attack ...... 9 
I. Infection Experiments 
Experimental Infection of Tubers ..... 10 
Experimental Infection of Living Plants .... 13 
Summary ......... 27 
II. Ecology akd Physiology of the Organisms 
1. Temperature Relations ...... 27 
2. Growth Habit -34 
3. The Carbon Sources of the Two Organisms ... 34 
Conclusions . . . . . . . . .42 
Bibliography ......... 43 
