"An advocate, by the sacred duty which he owes his client, knows, in the discharge of that office, but one person in the world, that client and none other . . . Nay, separating even the duties of a patriot from those of an advocate, and casting them, if need be, to the wind, he must go on reckless of the consequences, if his fate it should unhappily be, to involve his country in confusion for his client's protection."