422 * The Rev. P. KrrrH on the Origin of Buds. 
ground produced roots, and the part passing through the earth 
contained in the barrel produced also roots; but the other 
two portions produced branches. It was of little consequence 
whether the cuttings were inserted in the ground by the upper 
or under extremity, as relative to their original growth, and 
they vegetated even when made to pass through the barrel ho- 
rizontally. Hence Du Hamel concluded that germs both of 
the root and branch are dispersed throughout the whole extent 
of the plant, and are developed as the exigency of the case 
requires *. 
Others have contended that buds are generated only from the 
plexus of the vessels of the inner bark; because, perhaps, it is 
from the inner bark that the union of the graft and stock is 
effected in the well-known operation of grafting. 
Mr. Knight seems to have embraced the opinion of Du Hamel 
with some slight modifications. I do not mean to say that he 
has adopted the appellation, or even the notion of pre-organized 
germs. But he contends that buds are generated in the albur- 
num by means of the agency of the descending proper juice ; 
and thus dispersed, as we may infer, over the surface of the 
whole plant. His proof is as follows :—The runners connecting 
the tubers of a potatoe with the root were intersected and im- 
mersed by both portions in a decoction of logwood. The de- 
coction passed along in both directions. But it was in the di- 
rection of the tubers that the proof wanted was elicited. For 
there, the decoction was found to have passed through an ela- 
borate plerus of vessels between the bark and alburnum, which 
was seen to approach the skin at the base of the buds}. Hence 
it was inferred that buds are formed by the agency of the de- 
scending proper juice in its passage through the vessels of the 
inner bark. 
* Phys. des Arb. liv. iv. chap. v. T Phil. Trans. 1808, p- 289. 
Also 
