Vlll PREFACE 



forth the fundamental principles based upon the laws of 

 plant growth. 



The writings on these pruning investigations have 

 been quoted freely, the original investigator's own words 

 being used in preference to mine. This I feel simple 

 justice both to investigator and reader, because in any 

 re-statement something is sure to be lost. The reader 

 will herein find only slight condensations of the investi- 

 gators' original text. Among the writers so quoted are : 

 Professors Lewis of Oregon, Rioletti of California, Blake 

 of New Jersey, Whitten and Chandler of Missouri, Keffer 

 of Tennessee, Drinkard of Virginia, Howe and Gladwin 

 of New York, Selby of Ohio, Newman of South Caro- 

 lina, and Collins of the United States Department of 

 Agriculture. 



In the preparation of this volume I have found the 

 Experiment Station Record, published by the United 

 States Department of Agriculture, of immeasurable help 

 in searching for literature on pruning by means of its 

 abstracts and voluminous indexes. From it occasional 

 brief passages, mainly concerning foreign investigations, 

 have been copied, with credit to the original sources of 

 information instead of to the Record itself. 



My special thanks are due to Professor W. G. Brierley 

 of the University of Minnesota for photographs of prun- 

 ing tools (Figures 107, 108, 110, 114, 116 and 118) and 

 the legends which accompany them; to Mr. B. F. Wil- 

 liamson of New York, who made almost all of the pen 

 and ink drawings, either from rough sketches or from the 

 original sources in bulletins, reports, etc.; and to Mr. 

 E. T. Kirk of the Pennsylvania State College for photo- 

 graphs of local subjects, mostly gathered in the college 

 orchard and on the campus. The other photos, except 

 as specified under "Acknowledgments," were "snapped" 

 by my own camera, mainly at State College. Pa., and 

 developed by Mr. Kirk. 



