Plants are the reverse of animals in this respect. To man in

particular among the animals, on account of his erect stature, belongs

the characteristic of having his upper parts pointing upwards in the

sense in which that applies to the universe, while in the others these

are in an intermediate position. But in plants, owing to their being

stationary and drawing their sustenance from the ground, the upper

part must always be down; for there is a correspondence between the

roots in a plant and what is called the mouth in animals, by means

of which they take in their food, whether the source of supply be

the earth or each other's bodies.



2



All perfectly formed animals are to be divided into three parts, one

that by which food is taken in, one that by which excrement is

discharged, and the third the region intermediate between them. In the

largest animals this latter is called the chest and in the others

something corresponding; in some also it is more distinctly marked off

than in others. All those also that are capable of progression have

additional members subservient to this purpose, by means of which they

bear the whole trunk, to wit legs and feet and whatever parts are

possessed of the same powers. Now it is evident both by observation

and by inference that the source of the nutritive soul is in the midst

of the three parts. For many animals, when either part-the head or the

receptacle of the food-is cut off, retain life in that member to which

the middle remains attached. This can be seen to occur in many

insects, e.g. wasps and bees, and many animals also besides insects

can, though divided, continue to live by means of the part connected

with nutrition.

While this member is indeed in actuality single, yet potentially

it is multiple, for these animals have a constitution similar to

that of Plants; plants when cut into sections continue to live, and