Ketubot

and in that of terumah  of the tithe of demai  produce.  But does not Rab, however, follow [the rule of] assumption? Surely it was stated: As to the gift of a dying man  [in the deed of] which was recorded [symbolic] acquisition, the school of Rab in the name of Rab reported [that the testator] has [thereby] made him  ride on two harnessed horses;  but Samuel said: I do not know what decision to give on the matter. 'The school of Rab in the name of Rab reported [that the testator] has [thereby] made him ride on two harnessed horses', for it is like the gift of a man in good health,  and it is also like the gift of a dying man.  'It is like the gift of a man in good health', in that, if he recovered, he cannot retract,  and 'it is like the gift of a dying man' in that, if he said that his loan  [shall be given] to X, his loan [is to he given] to X.  'But Samuel said: I do not know what decision to give on the matter', since it is possible that he  decided not to transfer possession to him  except through the deed,  and no [possession by means of a] deed [may be acquired] after [the testator's] death!