236 PRINCIPLES OF BOTANY, ETC. 
and their nourishment, and on the genital organs of 
animals, compared with those of plants, which we 
cannot repeat here. In ancient times philosophers 
had such an idea, and Aristotle himself calls plants 
reversed animals, Linné proceeded even further, 
and we must make some allowance for his very 
lively imagination when we find him ealling heat the 
heart, and earth the stomach of plants, and, more 
justly, comparing the leaves to the lungs. 
§ 298. 
This likeness which philosophers observed be- 
tween animals and plants, chietly consisted in pro- 
‘perties, which organized bodies possess without re- 
spect to their structure, It is, therefore, certainly 
worth while, to consider more accurately, in what 
respects plants differ from anunals. 
Animals take food by a certain aperture, and 
have a particular canal by which they propel their 
excrementitious matter. 
Plants, on the contrary, take up nourishment with 
their whole surface, and possess, except transpira- 
tion by the leaves, which they have in common with 
animals, no peculiar canal to expel their excrements, 
except we consider the drops which we find on the 
roots of some luxuriant plants, (of which afterwar as, 
§ 275), as a proper instance. 
Plants have a structure altogether different from 
that of animals. ‘They want bones, muscles, and 
nerves, and only consist of variously combined 
vessels, which are surrounded by a cellular mem- 
brane. ‘The wood, which some have compared 
with 
