Fifty shares from a holding of 950 can be held on trust without being set apart; fifty bottles from a cellar cannot — and explaining why turns on the material in this chapter. It begins with the requirement itself: its place among the three certainties, the two elements that must both be satisfied, and what becomes of the property when a trust fails. It then examines which descriptions of trust property pass muster — why 'the bulk' fails while 'the residue' or a fraction of an identifiable whole succeeds — before tackling the tangible and intangible fungible asset divide and when segregation is needed. Finally it covers certainty of the beneficial interests, including the presumption where the instrument is silent, the position of discretionary trusts, and the failure of allocation mechanisms, closing with the key distinctions that the cases repeatedly turn on.
