Meaning of "with him strength took the form of wealth"

This is one paragraph from the story "The Wit of Porportuk" by Jack London

Porportuk became angry. His pride was touched; his strength was
challenged, and with him strength took the form of wealth. He would
not be ashamed for weakness before the world. El-Soo became
incidental. The savings and scrimpings from the cold nights of all his
years were ripe to be squandered. El-Soo stood at six thousand. He
made it seven thousand. And then, in thousand-dollar bids, as fast as
they could be uttered, her price went up. At fourteen thousand the two
men stopped for breath.

I don’t understand what the idiom "and with him strength took the form of wealth" means.
Also does "El-Soo became incidental" means that she became meaningless for him?

This is written somewhere around 1910, are the above two mentioned expressions used in todays American English?