PERIODICAI- LITEKATURK 87V 



The suggestion that phlogaphenes are accovmtable for the greater 

 (lurabiHty of heartwood is not convincing, for the following reasons : 



(i) Only a few species of trees have large enough amounts of 

 phlobaphenes to make any dilTerence in the durability of the wood un- 

 less phlobaphenes are extraordinarily toxic. 



(2) There is no evidence that phlobaphenes are any better preserva- 

 tives than tannin ; in fact, we should expect them to be less toxic, since 

 they are more inert chemically and less soluble. 



The phlobaphenes, which are anhydrides, not oxidation products, of 

 the tannin, form a series containing less and less water, the first of the 

 series often being indistinguishable from tannin and the others becom- 

 ing more and more insoluble. 



Mr. Stone's reasoning in one place is certainly ingenious. He had 

 previously spoken of the disappearance of lignin as accounting for 

 most of the reduction in weight of decayed wood and now says : "The 

 durability of wood is in proportion ... to the amount of lignin. 

 for the more there is, the longer it will naturally take to perish." This 

 is the same as reasoning that a block of mixed sugar and sand will with- 

 stand the action of water longer the greater the proportion of sugar 

 present, because the more sugar there is, the longer it will take to dis- 

 solve it. 



The implication that lignin is more liable to decay than cellulose is also 

 not warranted. Even in the first part of the same article attention is 

 called to a statement by Margell that "every fungus calls forth a specific 

 form of decay," and the recent work of Reseahisse^ and Palmer- indi- 

 cates that some fungi attack the cellulose more rapidly than the lignin. 



Hypotheses may sometimes be easier to proclaim than facts, yet to 

 the person with vision to see a possible interpretation of a conglom- 

 eration of facts a hypothesis, even though incorrect, is of first value ; 

 and this article of Mr. Stone's is illuminating, even though his assump- 

 tions are not well founded. H. D. T. 



"The Durability and Decay of Wood." Timber Trades Journal (LondonV 

 June 7, 1919. 



1 Jour. Ind. and Eng. Chem., vol. 9, pp. 284-7 (i9i7)- 

 - Unpublished report, Forest Products Laboratory. 



