This being so from the standpoint of pure physics, biology takes up the tale afresh, and devises means of its own for describing the particular ways in which things hang together in virtue of their being alive.

And biology finds that it cannot conveniently abstract away the reference to time.

It cannot treat living things as machines.

What does it do, then?
It takes the form of history.

It states that certain things have changed in certain ways, and goes on to show, so far as it can, that the changes are on the whole in a certain direction.