livery, and reread with due contrition. The persuasion that one's own infallibility is a myth leads by easy stages and with somewhat greater satisfaction to a refusal to ascribe infallibility to others. But dicta are not always ticketed as such, and one does not recognize them always at a glance. There is the constant need, as every law student knows, to separate the accidental and the non-essential from the essential and inherent. Let us assume, however, that this task has been achieved, and that the precedent is known as it really is. Let us assume too that the principle, latent within it, has been skillfully extracted and accurately stated. Only half or less than half of the work has yet been done. The problem remains to fix the bounds an the tendencies of development and growth, to set the directive force in motion along the right path at the parting of the ways.
The directive force of a principle may be exerted along the line of logical progression; this I will call the rule of analogy or the method of philosophy; along the line of historical de-
