414 FAST-GROWN TIMBER 



it will not expand those tubes, but it will add 500 more to its 

 original number in the same period of time. As regards the 

 cells, they may possibly be somewhat larger in plants of a 

 very soft texture when highly cultivated, than when wild, but 

 this is doubtful, and the difference between wild and cultivated 

 esculents principally depends upon the greater quantity of the 

 cells, and especially of the fluid matter contained in them. 

 Expansion, in the sense in which the writer above-mentioned 

 uses the word, has no existence. 



Now, the difference between esculent herbs and woody plants 

 consists mainly in this, that the former are composed principally 

 of cellular substance, and the latter of fibro-vascular. Any 

 addition to, not expansion of, the cellular tissue, renders plants 

 more brittle and more succulent, and therefore more fit to eat. 

 But it is most absurd to say that, therefore, any augmentation 

 of the quantity of fibro-vascular tissue will also render plants 

 more brittle ; on the contrary, it is an addition of toughness and 

 flexibility, and the only conceivable efi'ect its augmentation can 

 have wUl be to render timber yet stronger than before. 



With regard to Willows, Poplars, and other plants of that cha- 

 racter, they are not soft, because they grow fast ; for they are just 

 as weak when they grow slowly — and weaker. Their want of 

 strength and durability arises from their being unable to consoli- 

 date their tissue by depositing within it matter of Hghification. 

 The sap-wood of the Oak is as soft and perishable as Lime-wood, 

 and for the same reason ; namely, because that peculiar matter 

 which the Oak deposits ia its tissue, and which gives its heart- 

 wood strength, is not separated and deposited in the sapwood. 



The fact is, that so far as vegetable physiology is able to 

 throw, of itself, any Hght upon this curious subject, it would 

 lead to the conclusion that fast-grown timber is tougher than 

 slow-grown, and superior for all purposes of utility. 



The reader will be careful to observe, that in making these 

 remarks I intend them to apply only to the same kind of wood 

 wnder the same circumstances. Wood grown fast in one place 

 may be worse or better than wood grown slowly in some others ; 

 but that is a different question. 

 . As to the accuracy of these statements, evidence enough is to 



