Ante-Nicene Fathers, Vol VIII:
Pseudo-Clementine Literature.: Chapter XXVIII

Chapter XXVIII.—The Human Body.

“From all these things I think it is sufficiently and abundantly evident that all things are produced; and the universe consists by a designing sense, and not by the irrational operation of nature.  But let us come now, if you please, to our own substance, that is, the substance of man, who is a small world, a microcosm, in the great world; and let us consider with what reason it is compounded:  and from this especially you will understand the wisdom of the Creator.  For although man consists of different substances, one mortal and the other immortal, yet, by the skilful contrivance of the Creator, their diversity does not prevent their union, and that although the substances be diverse and alien the one from the other.  For the one is taken from the earth and formed by the Creator, but the other is given from immortal substances; and yet the honour of its immortality is not violated by this union.  Nor does it, as some think, consist of reason, and concupiscence, and passion, but rather such affections seem to be in it, by which it may be moved in each of these directions.  For the body, which consists of bones and flesh, takes its beginning from the seed of a man, which is extracted from the marrow by warmth, and conveyed into the womb as into a soil, to which it adheres, and is gradually moistened from the fountain of the blood, and so is changed into flesh and bones, and is formed into the likeness of him who injected the seed.