State responsibility — Kinds of — For taking of, or interference with, property — Mortgagee's interest — Nationalization of debtor corporation — Seizure of mortgaged property — Whether ground for an international claim — Whether loss to mortgagee too remote — The rule of proximate cause — Burden of proof on mortgagee claimant — Relevance of absence of “due process” in nationalization programme — Relevance of nature of interest created by mortgage on land according to local law.