HI. THE LEAF. 45 



water, and needs the same kind, though not the same 

 strength, of support ; and its ribs always are partly there- 

 fore constituted of strong woody substance, which is knit 

 out of the tissue ; and you can extricate this skeleton 

 framework, and keep it, after the leaf-tissue is dissolved. 

 So I shall henceforward speak simply of the leaf and its 

 ribs, only specifying the additional veined structure on 

 necessary occasions. 



10. I have just said that the ribs and might have said, 

 farther, the stalk that sustains them are knit out of the 

 tissue of the leaf. But what is the leaf tissue itself knit 

 out of ? One would think that was nearly the first thing 

 to be discovered^ or at least to be thought of, concerning 

 plants, namely, how and of what they are made. We 

 say they ' grow.' But you know that they can't grow out 

 of nothing ; this solid wood and rich tracery must be 

 made out of some previously existing substance. What is 

 the substance ? and how is it woven into leaves, twist- 

 ed into wood \ 



11. Consider how fast this is done, in spring. You 

 walk in February over a slippery field, where, through 

 hoar-frost and mud, you perhaps hardly see the small 

 green blades of trampled turf. In twelve weeks you wade 

 through the same field up to your knees in fresh grass; 

 and in a week or two more, you mow two or three solid 

 haystacks off it. In winter you walk by your currant-bush, 

 or your vine. They are shrivelled sticks like bits of 

 black tea in the canister. You pass again in May, and 



