VI PREFACE 



in underlying principles than in practices, and on the other, 

 that the laboratory and the supervised summer instruction 

 will become still more practical; and this we believe will 

 meet with the approval of the best informed fruit-growers 

 as well as educators. 



In the preparation of this book, the author has drawn 

 freely from the work of others. He has also invited several 

 of his colleagues to make suggestion and criticism of parts 

 of the manuscript. However, in no case was the final copy 

 submitted and, therefore, any errors that may occur devolve 

 entirely on the author. He is particularly indebted to Dr. 

 E. J. Kraus who offered many helpful suggestions and as- 

 sisted in the interpretation of some of the experimental work. 

 Similarly, Dr. F. E. Bear assisted with Chapters VIII and 

 IX, and Dr. M. J. Dorsey with Chapter XIII. Others who 

 read portions of the manuscript were Drs. W. H. Chandler, 

 J. K. Shaw, H. R. KraybiU and Prof. W. Paddock. To 

 James Macfarlane and J. L. Hayman thanks are due for 

 their kindness in preparing several of the drawings. 



Wooster, Ohio, J. H. GoURLEY. 



April 1, 1922. 



