Schr"odinger's unpublished hidden-variable model in the 1944-45 debate over the "Collapse of Determinism"

In the mid-1940s, the question of whether quantum mechanics could be supplemented by deterministic hidden variables resurfaced in a debate in textit Nature. I show that Erwin Schrödinger drafted a hitherto unpublished response to this controversy. In it, Schrödinger provided an explicit hidden-variable model, thereby showing that such models could not be ruled out. I reconstruct the historical context of this forgotten manuscript and publish here the first transcription and analysis. Importantly, Schrödinger's proposal should be understood as a proof of principle rather than as evidence of his commitment to determinism.