188 JOURNAL OF FORESTRY 



6. There seems to be little doubt that anatomical characters must 

 be largely dependent upon in the construction of a thoroughly accurate 

 and reliable key, such as is needed for general scientific purposes and 

 the use of technical experts in certain phases of commercial work. 



7. There are two methods of constructing such a key. The first 

 is the "trial and error" method of examining more and more material 

 until a key is secured which proves to be accurate and reliable. The 

 second method is logically more direct and scientific. This method 

 of attacking the problem is to study the limits of variability of ana- 

 tomical characters in different plants, to endeavor to isolate and 

 analyze the factors which control or regulate this variability, and to 

 attempt to formulate laws for forecasting the variability of selected 

 characters in a given species or environment. 



8. There are undoubtedly important economic fields of usefulness 

 for the student of plant anatomy in the study of problems connected 

 with the decay, seasoning, preservative treatment, pulping, chemical 

 utilization, and classification and identification of wood, but the busi- 

 ness man should realize the fact 'that the problems to be solved are 

 complex and difficult, and that results of economic value are not likely 

 to be secured without prolonged and painstaking work. 



DISCUSSION 



Dr. Fernoiv: 



But for the fact that the author has asked me to discuss his paper, 

 I would hardly have ventured to express myself on a subject with 

 which I have not particularly occupied myself for the last 20 years, 

 and then only by directing in a general way the timber physics work 

 of the old Forestry Division. My discussion must therefore take a 

 very general trend, mainly to accentuate the entirely sane position of 

 the author, and to express satisfaction in being able to subscribe un- 

 reservedly to the attitude of one who has specialized on the subject. 

 As for that, I could not conceive of any other. 



The most convincing proof of the difficulty of using anatomical data 

 for recognition of species came forcibly to my attention during the 

 timber physics work when a competent investigator, who had con- 

 structed a wood key based on anatomical characters, found in a lot of 

 samples, carefully collected in the woods and submitted to him, of 

 the four Southern commercial pines, 16 species represented. 



