989 PRINCIPLES OF BOTANY, ETC. 
wanting. Those juices which are salutary and ready 
prepared, are now deposited in the cellular texture, 
from which, most probably, the rest of the vessels 
receive them. The air-vessels, besides, inhale at- 
mospheric air, and the different matters dissolved in 
it, and decompose it into the necessary carbon and 
other constituent parts, by means of the light and 
vital power, to prepare them in the same’ way as 
those’ taken up by the root. 
"These air vessels, therefore, were we to compare 
them to the organs of the animal body, serve as 
lungs, mouth, stomach, mesentery and anus. 
§ 275. 
Yhe excrements of plants are not so considerable 
or conspicuous as those of most animals, as their 
food consists of water and air only. ‘They cannot, 
therefore, emit the superfluous matter which is of 
no further service to them, under any form, but that 
of air. ‘heir transpiration, (§ 239), and the gaseous 
fluids which they exhale, (§ 2773), prove this clearly. 
Mr Brugmanns, however, asserts even in them to 
have observed a particular excrementitious matter, 
which deserves farther’ notice. He saw in some 
luxuriant plants which he had in a glass vessel 
filled with earth, that during night there appeared 
on their radicles a drop of moisture, and observed 
distinctly, that when such a drop came in contact 
with the radicles of other plants not so luxuriant, 
the last soon became dry. If this happened re- 
peatedly, the plant decayed. He says he found that, 
; ‘Oats, 
