proper size, which never attains to any larger growth after it is first born ; this is called metamorphosis. But the more perfect animals with red blood are made by epigenesis, or the su- peraddition of parts. In the former, chance or hazard seems the principal promoter of generation, and there, the form is due to the potency of a preexisting material; and the first cause of generation is ' matter,' rather than ' an external efficient ;' whence it happens too that these animals are less perfect, less preservative of their own races, and less abiding, than the red-blooded terrestrial or aquatic animals, which owe their immortality to one constant source, viz. the perpetuation of the same species ; of this circumstance we assign the first cause to nature and the vegetative faculty.
Some animals then are born of their own accord, concocted out of matter spontaneously, or by chance, as Aristotle seems to assert, when he speaks of animals whose matter is capable of receiving an impulse from itself, viz. the same impulse given by hazard, as is attributable to the seed, in the generation of other animals. A^id the same thing happens in art, as in the generation of animals. Some things, which are the result of art, are so likewise of chance, as good health ; others always owe their existence to art; for instance, a house. Bees, wasps, butterflies, and whatever is generated from caterpillars by metamorphosis, are said to have sprung from chance, and therefore to be not preservative of their own race ; the con- trary is the case with the lion and the cock ; they owe their existence as it were to nature or an operative faculty of a divine quality, and require for their propagation an identity of species, rather than any supply of fitting material.
In the generation by metamorphosis forms are created as if by the impression of a seal, or, as if they were adjusted in a mould ; in truth the whole material is transformed. But an animal which is created by epigenesis attracts, prepares, ela- borates, and makes use of the material, all at the same time ; the processes of formation and growth are simultaneous. In the former the plastic force cuts up, and distributes, and re- duces into limbs the same homogeneous material ; and makes out of a homogeneous material organs which are dissimilar. But in the latter, while it creates in succession parts which are differently and variously distributed, it requires and makes a
