I found out something interesting regarding the salivation. If you store your salivation for some days you might notice that it colors the walls of the container with something greenish. At first I thought it could be copper, it looks a bit like greenish copper stains from copper pipes. But no, I stumbled upon a much better explanation, when I researched myeloperoxidase (MPO) and glutathione peroxidase, as mercury interferes with the production of these essential enzymes.

http://en.wikipedia.org/wiki/Myeloperoxidase

"MPO has a heme pigment, which causes its green color in secretions rich in neutrophils, such as pus and some forms of mucus."

Here we have some real evidence, that the salivation comes from neutrophil activity, and they don't attack mercury for sure, but instead pathogens like candida. This also explains the sour taste of the salivation, contains acid: "MPO produces hypochlorous acid (HOCl) from hydrogen peroxide (H2O2)".
The neutrophils use this acid to attack the pathogens. Routine testing of MPO is not performed.