sulfite solution and hydroquinone

Hi All,

While going through an old book on Photography by
L.P.Clerc(Photography: theory and practice), I came across the
following interesting piece:

"Sulfite solutions do not keep well, therefore preparation of solution
is not advised. If absolutely necessary, a 20 percent solution can be
prepared and a small quantity (5 %) of either p-aminophenol or
hydroquinone can be added to protect the sulfite solution."

I forget the exact words, but the above is the essence.

I am really surprised. I have always assume that it is sulfite that
protects developing agents like hydroquinone and aminophelos, and here
I see the opposite.

So when we prepare D-76 and D-72, are we protecting the hydroquinone
or the sulfite!!??

rgds,
Sreenath