146 Forestry Quarterly 



phenols are produced by combinations of the wood substance 

 with these bodies, the hydrochloric acid serving as a medium. 



2. Wood substance is not a chemical individual, but consists 

 of vanillin, methyl furfurol, pyrocatechuic acid, coniferin which 

 are partly combined with the cellulose of the membrane in ether 

 combination, partly are dissolved in the resin, and exist only to 

 small part uncombined in the membrane. 



3. The ether combination may be broken up by hydrolysis with 

 diluted acids or alkalis. To obviate the formation of resinous 

 combinations of furfurol, which are difhcult to remove from 

 the wood, water at 180° in vacuum or an electric current must 

 be employed. 



4. The intensity of the coloration even when only the smallest 

 traces of wood are present, is explained by the sensitiveness of 

 the phenol colors and by the exceedingly fine distribution of 

 these substances through the resin, as well as by the capacity of 

 cellulose to retain substances tenaciously. 



5. The average methyl number of wood substance is 48. 



6. The possibility of securing in a simple manner methyl fur- 

 furol and pyrocatechuic acid from cellulose, and the fact that 

 vanillin may also be derived from the lignified membrane make 

 it probable that wood substance is derived from cellulose. Wies- 

 ner's reactions are therefore undoubted proofs of lignification. 



Uniersuchungen iiber die Holzsubstanz vom chentisch-physiologischen 

 Standpunkte . Centralblatt fiir das gesauiintt; For.->twesen, Feb., 1906, 

 PP- 93-94. 



Causes for the dropping of branch- tips of 

 Again the Norway Spruce, which often takes 



Spruce place during winter and spring have again 



Droppings. and again been discussed. Squirrels have 



been held responsible, but the number of 

 such droppings are against the theory. Periodicity and con- 

 nection with seed years has been suggested, but the appearance 

 of the droppings does not allow conclusion of an organic process. 

 Frost producing brittleness and wind storms mechanically 

 breaking off the tips by whipping them against each other first 

 suggested by Ratzeburg, seems a plausible cause. 



Dr. vSedlaczek records that he has found in the forest invariably 

 the buds on the droppings injured, indicating at least participa- 

 tion of squirrels, but the droppings were also observed after 



