I50 THE LAHCH. 



incessant and powerful strain, however, caused by the 

 additional annual layers of wood from within the bark, 

 and the rupturing of the longitudinal vessels of the 

 liber, often so completely obliterate the divisions of the 

 layers that they are very indistinct, and sometimes 

 impossible to count from that cause, otherwise the age 

 of the tree could be as accurately ascertained from the 

 layers of the bark as from the layers of the wood. 

 The parenchyma of the young shoot is converted into 

 liber in the first place, and then the liber excretes 

 what in turn becomes the parenchyma proper. The 

 membrane between the alburnum or sapwood and 

 the epidermis or outer covering of the bark has a very 

 wonderful part to perform in the economy of the tree's 

 growth. From the alburnum the substance termed 

 the liber is secreted. The parenchyma is secreted 

 from the liber, and again the epidermis from the 

 parenchyma. There is, therefore, as respects the whole 

 progress of the growth of the bark, an endogenous 

 process carried on from first to last, from the forming 

 of the primary section or shoot to the maturation of 

 the monarch centuries old. 



It may be said of the larch tree as of clean fish — 

 every part is useful, and none should be thrown away, 

 neither flesh, bones, fins, nor skin. The bark of the 

 larch is of very considerable commercial value, and, 

 after paying expenses of peeling and harvesting, &c., 

 leaves a favourable balance in its favour, generally 

 about half that of the oak. 



Amongst other examples that have come under my 



