ANATOMY OF PLANTS. 191 



fruits. Finally, the nature and structure of many fruits are 

 quite inconsistent with this origin, since the soft, spongy, and 

 entirely cellular pith cannot possibly generate organs, which 

 are often as hard as bones, and therefore contain a crowd of 

 spiral-vessels and sap-vessels, which are entirely wanting in 

 the pith. 



Besides, the use of the pith is evidently altogether confined to 

 the time when the young shoots are sent out, when the connec- 

 tion between its cells and the radiated cell-vessels of the wood 

 seems to be subservient to the deposition and preparation of 

 the sap. In more advanced age, when the formation of wood 

 takes place, the radiated vessels themselves afford the means 

 of this deposition, and render the pith cells superfluous. 

 Hence we often enough observe, that in hollow trees, while 

 not only the pith, but the whole of the wood is destroyed, 

 they yet continue to grow, provided only the inner bark 

 remains. 



IV. On the Structure of Buds. 



F. C. Medicus's Beytra^-e zur Pflanzen-Anatomie. Manheim, 1799, 

 1801. 



Dessen^s Pflanzen-physiologische Abhandlungen. Leipsig, 1803. 



Darwin's Phytonomia. 



Aubert du Petit-Thouars* Essay on the Organization of Plants. Paris, 

 1806. 



302. 



We must first establish a general idea respecting germs, 

 before we proceed to a more particular consideration of the 

 formation of buds, because these latter are only germs un- 

 folded, and matured into a variety of shapes, although in 

 Latin, and its kindred dialects, the word Gemmae is used as 

 well for germs as for buds. By genns, we understand every 

 condensation of the peculiar juices, or of the particular matters 

 from which new individuals of the same kind can be produ- 

 ced. In their simplest fomi these germs may be observed in 

 the small granular or spherical bodies, which arc produced in 



