Chapter I.

1. The nature of animals and their mode of reproduction has now been described. Their actions and mode of life also differ according to their disposition and their food. For almost all animals present traces of their moral dispositions, though these distinctions are most remarkable in man. For most of them, as we remarked, when speaking of their various parts, appear to exhibit gentleness or ferocity, mildness or cruelty, courage or cowardice, fear or boldness, violence or cunning; and many of them exhibit something like a rational consciousness, as we remarked in speaking of their parts. For they differ from man, and man from the other animals, in a greater or less degree; for some of these traits are exhibited strongly in man, and others in other animals.

2. Others differ in proportion. For as men exhibit art, wisdom, and intelligence, animals possess, by way of compensation, some other physical power. This is most conspicuous in the examination of infants, for in them we see, as it were, the vestiges and seeds of their future disposition; nor does their soul at this period differ in any respect from that of an animal; so that it is not unreasonable for animals to present the same, or similar, or analogous appearances. Nature passes so gradually from inanimate to animate things, that from their continuity their boundary and the mean between them is indistinct. The race of plants succeeds immediately that of inanimate objects; and these differ from each other in the proportion of life in which they participate; for, compared with other bodies, plants appear to possess life, though, when compared with animals, they appear inanimate.

3. The change from plants to animals, however, is gradual, as I before observed. For a person might question to which of these classes some marine objects belong; for many of them are attached to the rock, and perish as soon as they are separated from it. The pinnæ are attached to the rocks, the solens cannot live after they are taken away from their localities; and, on the whole, all the testacea resemble plants, if we compare them with locomotive animals. Some of them appear to have no sensation; in others it is very dull. The body of some of them is naturally fleshy, as of those which are called tethya; and the acalephe and the sponge entirely resemble plants; the progress is always gradual by which one appears to have more life and motion than another.

4. In the vital actions also we may observe the same manner. For vegetables which are produced from seed appear to have no other work beyond reproduction; nor do some animals appear to have any other object in their existence. This object then is common to them all; but as sensation advances, their manner of life differs in their having pleasure in sexual intercourse, in their mode of parturition and rearing their young. Some of them, like plants, simply accomplish their peculiar mode of reproduction at an appointed season, and others are diligent in rearing their young; but as soon as this is accomplished they separate from them, and have no farther communication; but those that are more intelligent, and possess more memory, use their offspring in a more civilized manner.

5. The work of reproduction is one part of their life, the work of procuring food forms another. These two occupy their labour and their life. Their food differs in the substances of which it consists, and all the natural increase of the body is derived from food. That which is natural is pleasant, and all animals follow that which is pleasant to their nature.