398 CONSERVATIVE ORGANS. [LECT. VIII. 



of the plant. The quantity of amylaceous gra- 

 nules 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 pro- 

 bable that the lobes which surround it, perform 

 for it a similar function to that of the cotyledons, 

 or seed-lobes, as connected with the embryon en- 

 closed within them, or that of the leaves in re- 

 ference to the stem and branch ; which we shall 

 afterwards prove to be analogous to that of the 

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

 the leaf above the bud supplies part of the pabu- 

 lum which is elaborated into the new branch ; for, 

 until its own leaves are expanded in spring, and 

 capable of producing that change on the sap which 

 converts it into proper juice, no alburnous mat- 

 ter can be formed by them. The descending juice, 

 however, from the leaf above the germ, is not 

 conveyed to it by any vascular communication, but 

 deposited in the cellular mass or placenta, if it may 

 be so termed, on which it is seated; and by which 

 alone it is connected with the medullary sheath of 

 the parent shoot. In the germ or vital speck, thus 

 situated and supplied with nutriment, the organiza- 

 tion of the branch commences as from a centre. It 

 is not probable that we shall, ever, be able to trace 

 every minute change, which occurs from this period 

 until the first rudiment of the new branch is per- 

 spicuous, even by the aid of the best microscopes ; 



