VI PREFACE TO SECOND EDITION. 
edition is a considerable extension of the treatment of bacterial 
diseases of plants that have received so much investigation in the 
last ten years. With these additions it is hoped that the present 
edition will be a fair summary of our present information upon the 
relation of germ life to agriculture. 
H. W. C. 
MIDDLE-TOWN, CONN. 
June 15, 1909. 
