LAllCH. 



79 



and deficiency of putrescent matter in the ground, 

 or other more obscure agencies connected with pri- 

 mitive ranges, may have some influence to counter- 

 balance unsuitableness of soil. It is not probable 

 that the coolness and moisture of altitude would be 

 necessary in Scotland to the healthy growth of a ve- 

 getable which flourishes under Italian suns, on the 

 general level of the Appenine and on the Sardinian 

 hiUs. 



The rot, so general in growing larch, though some- 

 times originating in the bulb or lower part of the 

 stem, seems to have its commencement most frequent- 

 ly in the roots. Thence the corruption proceeds 

 upwards along the connecting tubes or fibres into 

 the bulb, and gradually mounts the stem, which, 

 when much diseased, swells considerably for a few 

 feet above the ground, evidently from the new 

 layers of sap-wood forming thicker to afford neces- 

 sary space for the fluids to pass upward and down- 

 ward — the matmed w^ood through which there is no 

 circulation approaching at this place within one or 

 two annual layers of the outside. In a majority of 

 cases, the rot commences in the roots which have 

 struck down deepest into the earth, especially those 

 under the stool ; these having been thrown to a con- 

 siderable depth by the young plant, as the tree en- 

 larges, are shut out from aeration, &c. by the supe- 



