I've been transcribing, validating, and annotating the Wasserliesch Familienbuch (1752-1899) prepared by Peter KOHNS. Out of copyright concerns, I've tried repeatedly to locate Mr. Kohns. So far, no luck.
He was also an authority on orchids and lilies, and published a few articles on that topic.
I suspect he died in the 1990s. If you have information about him, please contact me.