~ In mir ist Wahrheit ~
The scene on the front clearly depicts an alchemist in his laboratory (The Thewalt Catalog calls this "the Studying Pharmacist".) and suggests that this could be an occupational stein for a chemist or an apothecary. The verse is a satire indicating that since science is based on truth, one will not be exposed to poison by drinking from such a stein. It is marked on the front "Paulus & Thewalt Hoehr" and impressed on the bottom is the trade mark of Albert Jacob Thewalt, Germany and the number 536, ca. early 1900's.
In mir ist Wahrheit,
Ich kann nicht trügen.
Gift trinkt man nicht
Aus solchen Krügen.
In me is truth,
I cannot lie.
Poison is not drunk
from such steins.

Translation: Roy De Selms
Photo credit: unknown