Henry David Skidreau
"That man is the richest whose pleasures are the cheapest."
First Mention: WB2014 Digdoug - Episode 20
"Doctor" Henry David Skidreau is the creator of the Tonic of Wildness, a very poor liquor that, while cheap, was described as a slow poison. Like "Doc" Herbert Sassafras it's not known and doubtful he's legitimately earned the Healomancer title of Doctor.
The good doctor probably has a source of fermentable fruit or vegetables and a still of some kind. Alternately, he may have found a way to use Healomancy (or Hippiemancy) to make normal juice into liquor... with mixed results.
Real World Reference
He is a reference to "Skid Row" and Henry David Thoreau. Skid Row is an expression for someone who is destitute and poor. Thoreau was a famous for the book "Walden", about living alone by one's own effort amid nature.
The Tonic of Wildness refers to this quote from Walden:
We need the tonic of wildness...At the same time that we are earnest to explore and learn all things, we require that all things be mysterious and unexplorable, that land and sea be indefinitely wild, unsurveyed and unfathomed by us because unfathomable. We can never have enough of nature.