I 
Irritability of Vegetables. , 161 
thrufls itfelf between their filaments, and almoft unavoidably 
touches them in the moft irritable part : thus the impregnation 
of the germen is performed ; and as it is chiefly in fine funny 
weather that infeds are on the wing, the pollen is alfo in fiucli 
weather moft fit for the purpofe of impregnation. It would 
be worth while to place a branch of the Barberry flower in 
fuch a fituation, as that no infed, or other irritating caufe, 
could have accels to it ; to watch whether in that cafe the an- 
therie would ever approach the (ligma, and whether the feeds 
would be prolific. 
I have been the more particular in thefe o'bfervations upon 
the Barberry, becaufe although feveral authors mention the 
irritability of its {lamina, none, that I can find, have related 
ill what part of the (lamina this property refides, or the pur- 
pofe it ferves ; at lead they have not purfued their inquiries 
with any great degree of accuracy, but feem moflly to have 
copied one another. Gmelin, who has written a diflertation 
expreflly on the irritability of vegetables, has fcarcely any 
thing new on the fubjed ; the chief part of his work is a cata- 
logue of plants which he found not to be irritable. 
The Barberry is not the only plant which exhibits this phe- 
nomenon. The (lamina of Callus Tuna y a kind of Indian Fig, 
are like wife very irritable. Thefe (lamina are long and (len- 
der, (landing in great numbers round the infide of the flower. 
If a quill or feather be drawn through them, they begin in the 
fpace of two or three feconds to lie down gently on one fide, 
and in a fhort time they are all recumbent at the bottom of the 
flower. The motions in Diana? a mujcipula, Mimofa J'enfitiva 
and pudica , are too well known to be mentioned here. A fimi- 
lar phenomenon has been obferved, where indeed an obvious 
botanical analogy would lead one to exped it, in the Drofera. 
Vol. LXXVIJI. Y See 
