I see this is an old thread, but there is some misinformation here.
Originally Posted by mandalinn82
First, the skin is, for the most part, an impermeable membrane
This is not true. If the skin was impermeable then nicotine patches would not work, because the skin would not absorb the medicine from the patch. Pain relief patches would not work and neither would birth control patches. The skin IS permeable and that's why all these various patches work.
You can do and experiment. Have someone cut a clove of garlic and rub it on the bottom of your foot. In a few minutes you will taste garlic.
The skin acts as a barrier which does prevent bacteria from freely entering the body. The circulatory system is basically a closed system, that is why we are not seeping blood. We bleed when tiny capillaries in the skin are cut.
I believe 20/20 did a recent story on these patches and found them to be bunk. As another poster stated, when the pads got damp, they changed color.
... as you were