"The common law does not consist of particular cases decided upon particular facts: it consists of a number of principles, which are recognised as having existed during the whole time and course of the common law. The Judges cannot make new law by new decisions; they do not assume a power of that kind: they only endeavour to declare what the common law is and has been from the time when it first existed. But inasmuch as new circumstances, and new complications of fact, and even new facts, are constantly arising, the Judges are obliged to apply to them what they consider to have been the common law during the whole course of its existence, and therefore they seem to be laying down a new law, whereas they are merely applying old principles to a new state of facts."