ATTACHiVfENT OF BRANCHES. 279 



the stem or branch, in which it is seated, merely by 

 cellular matter. The effect of the organic power on 

 it is the addition of new matter, and the consequent 

 evolution of its parts ; till gradually extending in the 

 direction of its axis, it unites with and becomes a per- 

 manent part of the plant. The quantity of amylace- 

 ous granules contained in the cells surrounding the 

 germ, renders it probable that it receives its first nou- 

 rishment from this source ; and it is not less probable, 

 that the lobes which surrounded it, perform for it a 

 similar function to that of the cotyledons, as connected 

 with the embryon inclosed within them, or that of the 

 leaves in reference to the stem and branch ; which we 

 shall afterwards prove to be analagous to that of the 

 lungs in animals. But it is, also, probable that the 

 leaf above the bud supplies part of the pabulum which 

 is elaborated into the new branch ; for, until its own 

 leaves are expanded in spring, and capable of produc- 

 ing that change on the sap which converts it into pro- 

 per juice, no alburnous matter can be formed by them. 

 The descending juice, however, from the leaf above 

 the germ, is not conveyed to it by any vascular com- 

 munication, but deposited in the cellular mass or pla- 

 centa, if it may be so termed, on which it is seated; 

 and by which alone it is connected with the medul- 

 lary sheath of the parent shoot. In the germ or vital 

 speck, thus situated and supplied with nutriment, the 

 organization of the branch commences as from a cen- 

 tre. It is not probable that we shall ever be able to 

 trace every minute change, which occurs from this pe- 

 riod until the first rudiment of the new branch is con- 

 spicuous, even by the aid of the best microscopes ; 

 but the first part that can be distinctly recognised is 

 the pith, which, in a longitudinal section of the green 

 twig of the Lilac, made three weeks after its protrusion 

 from the bud, and the appearance of the germ on its 



