Therefore we do not affirm that the animal is produced without a principle of its being; but we call the principle that power which changes, mixes, and tempers the matter, so that a living creature is regularly produced; but the egg is an after-production, as the blood or milk of an animal after the taking in and digestion of the food.

For we never see an egg formed immediately of mud, for it is produced in the bodies of animals alone; but a thousand living creatures rise from the mud.

What need of many instances?
None ever found the spawn or egg of an eel; yet if you empty a pit and take out all the mud, as soon as other water settles in it, eels likewise are presently produced.

Now that must exist first which hath no need of any other thing that it may exist, and that after, which cannot be without the concurrence of another thing.

And of this priority is our present discourse.