97 
the tnie Sap of Trees is deposited during Winter. 
Ingenhouz prove that their action on the air which surrounds 
them is very essentially different from that of full grown 
leaves. It is true that buds in many instances will vegetate, 
and produce trees, when a very small portion only of albur- 
num remains attached to them ; but the first efforts of vege- 
tation in such buds are much more feeble than in others to 
which a larger quantity of alburnum is attached, and therefore 
we have, in this case, no grounds to suppose that the leaves 
derive their first nutriment from the crude sap. 
It is also generally admitted, from the experiments of 
Bonnet and Du Hamel, which I have repeated with the same 
result, that in the cotyledons of the seed is deposited a quantity 
of nutriment for the bud, which every seed contains ; and 
though no vessels can be traced* which lead immediately 
from the cotyledons to the bud or plmnula, it is not difficult to 
point out a more circuitous passage, which is perfectly similar 
to that through which I conceive the sap to be carried from the 
leaves to the buds, in the subsequent growth of the tree ; and 
I am in possession of many facts to prove that seedling trees, 
in the first stage of their existence, depend entirely on the 
nutriment afforded by the cotyledons ; and that they are 
greatly injured, and in many instances killed, by being put to 
vegetate in rich mould. 
We have much more decisive evidence that bulbous and 
tuberous rooted plants contain the matter within themselves 
which subsequently composes their leaves ; for we see them 
vegetate even in dry rooms, on the approach of spring ; and 
many bulbous rooted plants produce their leaves and flowers 
with nearly the same vigour by the application of water only, 
MDCCCV. 
