It is impossible for fire to consume its nourishment without at the same time giving back what it has consumed already. For all his condemnations of Pythagoras, Heraclitus cannot get away from the tuned string. With all his originality, Heraclitus remains an Ionian. In a sense, Heraclitus substituted fire for the 'air' of Anaximenes, who in turn had substituted 'air' for the water of Thales. Also, Hereclitus' notion of flux is a development of that Anaximenes' notion of rarefaction and condensation.
Some fragments superficially appear to assert the immortality of the individual soul.
But, when we examine them, we see they cannot bear this interpretation. Soul is only immortal in so far as it is part of the everliving fire which is the life of the world. It is not only true that we cannot step twice into the same river, but also that we are not the same for two successive instants. That is just the side of his doctrine that struck contemporaries most forcibly, and Epicharmos already made fun of it by putting it as an argument into the mouth of a debtor who did not wish to pay.