PHYSIOLOGY. 251 
From the first arises the root, from the last the 
trunk, or the part above ground. Cutting a ger- 
minating plant in a perpendicular direction, so as to 
divide it in two equal parts, we observe in the middle 
of each cotyledon a hollow channel which is called 
the chyliferous duct, (Ductus chyliferus), which is 
continued as far as the beginning of the rostel, pro- 
ceeds between its pith and fleshy substance, and at 
last incloses the pith. ‘This duct serves to conduct 
the nourishing fluid, which the cotyledons contain, 
to the young plant. Ixperience teaches us, that 
germinating plants, even though they have some 
leaves already evolved, cannot part with their co- 
tyledons without endangering their lives, like a 
young animal which cannot want the feeding breast 
of its mother*. 
§ 245. 
It is a remarkable phenomenon in the germina- 
tion of seeds, that the radicle first elongates, and 
pushes into the earth, where as soon as it fixes itself, 
and not sooner, the plumule appears in its peculiar 
* According to my own experience, the rostel dries up en- 
tirely, if immediately after the seed begins to germinate, we 
cut off both cotyledons, and all vegetation ceases. Fabbroni, 
however, says, that a young plant may lose half of its cotyle- 
dons without any bad effects, and he ,even has cut off the 
whole, and the vegetation went on. But’ probably this ex~ 
periment was made on plants where the plinnule was already 
somewhat large. Hedwig observes, that the plumule may be 
cut off, and that in its place two young shoots will appear. 
J doubt very much if this be the case with all plants. 
shape, 
