53 



hyacinths grown in transparent glasses 

 do not turn green. This is true of them, 

 and also of the silver ends of woody roots ; 

 but it must be recollected that to neither 

 of these can the air be admitted when 

 they grow in water, or light when they 

 grow in earth. It is however, I believe, true 

 of both these, under any circumstances. 

 But when part of a woody root is acci- 

 dentally exposed by the wearing away of 

 a bank, &c., the layer below the outer 

 cuticle will be found green, precisely the 

 same as on a branch, though where the 

 root goes under ground, both nearer and 

 farther from the stem, the under layer 

 will be white. The layer under the outer 

 cuticle may also be observed green at the 

 commencement of the root when it is 

 accidentally exposed near the neck of the 

 plant. This is not a matter of opinion, 

 but a matter of fact, and we have only to 

 use our eyes to see it. 



Each layer of bark is supposed to have 

 D 3 



