Date: 20 Kislev 5574
From: Rabbi Moshe Sofer
To: Rabbi Simcha Bunim Ginz (Eiger)
The Chasam Sofer rejects his father-in-law's distinction between tenai and shiyur as applied to gifts and sales, arguing it belongs only to the domain of gittin where complete krisos is required. He explains that matanah al menas lehachzir is a complete, absolute transfer — if the giver waives the condition no new kinyan is needed — whereas kinyan peiros never conveyed the guf at all; thus the esrog satisfies lachem while a field subject to Yovel reversion does not satisfy the declaration of divine gift for bikkurim.
Source: Shu"t Chasam Sofer CM §131