ROLE OF THE MICROSCOPE 189 



We have fortunately arrived at a period in the world's development 

 when the call is general for a scientific basis of our practice. But 

 I fear that our enthusiasm in that direction sometimes slops over 

 and leads us to expect at once more result than it is practically possible 

 to attain. Often much preliminary work needs to be done before we 

 can attack the practical problem directly. Yet practical problems 

 have no time to wait, and hence it is natural that they are solved 

 perhaps not in a scientific and the best way, but out of hand in the 

 best possible way for the time, and until a reliable scientific basis is 

 found. 



Perhaps the author might have accentuated more strongly the need 

 of keeping the objects of any investigations clearly in view, at least 

 in so far as a distinction can be made into practical issues and 

 scientific basis work. 



As regards the practical issue in the construction of a wood key, I 

 would call attention to the fact that the user of wood is much less con- 

 cerned with botanical relationship of his material than with its quality, 

 and as a rule, it is average quality that he seeks. If there are ten 

 species of white oak which exhibit practically the same qualities he 

 is perfectly willing and justified to substitute one for the other. A 

 number of species or even genera furnish the mahogany of the trade. 

 and, in most cases, I take it, satisfactorily. Habit and fashion to a 

 large extent direct the use of wood: the white pine, the king of the 

 woods, found it difificult to be considered in Great Britain in the 

 forties, and in Germany much later. These examples are to serve the 

 purpose of showing that accuracy in botanical determination is to 

 the consumer in many cases irrelevant ; quality, which he is accustomed 

 to connect with names, is all he is concerned with. In other cases, 

 to be sure, it is of importance to be able to recognize the species : the 

 difficulty of distinguishing the wood of the Southern pines 'is a 

 serious handicap, but, as the author hints, a key based on microscopic 

 inspection would hardly satisfy the user; he would be deterred from 

 using it in wholesale inspection. 



There is one practical issue, in which an accurate determination is 

 desirable, that interests the forester, more particularly the silviculturist 

 of the future. It is quite certain that the silviculturist of the future 

 will dispense with the many species that nature offers him, and will 

 have to choose among those of similar wood character the ones that 



