http://www.britannica.com/EBchecked/topic/125898/colloid
http://www.mayoclinic.com/health/colloidal-silver/AN01682
It doesn’t sound like colloidal silver to me. Siver ions are completely dissolved like the sodium ions in table salt in water. Colloids are suspensions; colloidal silver sounds like a suspension of elemental silver, not a silver salt. Silver salts have been used on wounds in medicine for a while, typically burns.
If you think about it, though, before the advent of cheap stainless steel, most people ate off of silver plate or silver utensils, even if the base metals were showing through. I would expect trace amounts of silver ended up in their system, and people seemed healthier (although I'll admit nostalgia may colour my memories). Cooking was done in cast iron, and after no-stick (Teflon, because good and well-seasoned cast iron is pretty much non-stick) cookware came out, it seemed like a lot more people had anemia, too.
As for the colloidal silver, I would not expect that to remain metallic in the digestive tract, but would end up as a silver salt (likely a chloride). The trick, of course is not to overdo it. The fellow who has the blue complexion made his own and ODd.
Btw, I prefer Tea Tree Oil on minor burns, after cold running water. Pain relief, and no blistering.