FORMATION OF THE WINTER LEAF BUD. 



295 



almost wholly of the bark and inner bark, so the flower bud 

 is a composition of every part and juice of the tree. 



The leaf bud is generally smaller than the other two; in The leaf bud. 

 its first state it consists of two or three scales, enclosing a 

 parcel of vessels, which have the appearance of a coarse 

 kind of cotton, very moist ; but when drawn out, and placed 

 in the solar microscope, they show themselves to be merely 

 the vessels of the bark and inner bark elongated and curling 

 up in various forms. They are generally of three sorts, like 

 the bark, &c. First three or four short thick ones that ap- 

 pear to grow from the larger vessels of the inner bark, and 

 through which the thickened juice flows, but with this dif- 

 ference, that the holes are not there. Then there are two 

 smaller sized vessels, that exactly resemble the smaller ves- 

 sels fff the bark. The former I have ever found to be the 

 midrib of the leaves; the latter the interlacing of the smal- 

 ler vessels : and I have so often taken a leaf and dissected it 

 to compare it with the vessels which I the next winter found 

 in the leaf bud of the same tree, that I cannot but feel the 

 most thorough conviction, that I have in the bud traced its ori- 

 gin; though certaiuly much enlarged in the full grown leaf. 

 The pabulum of the leaf, or that which lies between the 

 vessels, is (as I have before said,) composed of that thick 

 juice which runs in the bark or inner bark of the tree, and 

 is to be found in no other part, It differs essentially from 

 the sap, and may be called the blood of the tree, as it pos- 

 sesses its peculiar virtues, is gum in one, resin in another, 

 oil in a third, according to the nature of the plant. Whe- 

 ther it flows both forward and retrograde I have not yet 

 been able to discover; indeed, finding the subject in the 

 Jiands of a gentleman of such abilities as Mr. Knight, I j^ t Knight, 

 waited his decision : but that the greatest part is taken up 

 in forming the leaves I feel the most perfect conviction. 

 The pabulum of the leaf, after the vessels are arranged and 

 crossed, grows over in bladders, making alternate layers with 

 the smaller pipes, and'with the branches of the leaf. But 

 I have found, and shall give, many specimens before this part 

 of the process is begun. 



I know not any tree that gives a more convincing proof Formation of 

 of the manner of forming leaves in the bud than the horse- the leaf of the 



chestnut : hgrsecbestnut - 



