38 TIMBER AND SOME OF ITS DISEASES. [CH. 11. 



in all their details : my object is served by showing 

 how well worthy of the necessary scientific study is 

 timber even to those who are only concerned with it 

 in its usual conditions, and within those limits of 

 variation in structure and function which constitute 

 health. The importance of the subject in connection 

 with the modern development of biology along the 

 grand road of comparative physiology, does not need 

 insisting upon here. It will be the object of further 

 chapters to show how it is, if possible, still more 

 important and interesting to know the structure and 

 functions of healthy timber, before the practical man 

 can understand the diseases to which timber is 

 subject. At the same time it must be clearly borne in 

 mind that these are but sketches of the subject ; for 

 it is as true of trees and their diseases as it is of men 

 and human diseases, if you would be trainers and 

 doctors you must know thoroughly the structures and 

 peculiarities of the beings which are to be under your 

 care. 



