In book 19 of the Odyssey, what is Odysseus up to when he asks for an old retainer, the "soul of trust" to bathe his feet?

Odysseus is continuing the slow and deliberate process of
returning home and allowing certain people to recognize him so that his return will be
on his terms rather than according to someone else's.  He knows that the wound that
Eurycleia will be cleaning is in a place that she will see the old scar that will prove
that he is in fact Odysseus.  Even after she sees it and spills all the water in her
joy, he makes sure that she will not tell anyone else.

As
Odysseus limits all the knowledge of his return, he continues to control the entire
process.  It is also an interesting section in terms of the narrative process as it is
told strictly through the narrator's eyes and also gives us another flashback to the
past when Eurycleia served as the nurse to Odysseus and his mother at his
birth.