Irritability of Vegetables. 165 
deligned, the vital principle was much fooner exhausted than in 
thole which had known no fuch Itimulus. It is, perhaps, for 
the lame reafon that double flowers, in which, the organs of 
generation being obliterated, no impregnation can take place, 
laft much longer in perfection than fingle ones of the fame 
fpecies, as is notorioufly the cafe with Poppies, Anemonies, 
6cc. In fingle Poppies the corolla falls off in a few hours ; but 
in double ones it lalts feveral days ; and this may polhbly, 
combined with other obfervations, lead to a difcovery of the 
real ufe of the corolla of plants, and the fhare it has in the 
impregnation, about which there has yet been no probable 
conjedure. 
