58 HARVARD LAW REVIEW, the procedure. He awaits the action of his adversary ; and it is enough if he simply repel hini. The reus has no duty of satisfying the court ; it may be doubtful, indeed extremely doubtful, whether he be not legally in the wrong and his adversary legally in the right, and yet he may gain and his adversary lose, simply be- cause the inertia of the court has not been overcome, or, to use the more familiar figure, because the actor has not carried his case beyond the point of an equilibrium of proof, or, as the case may be, of all reasonable doubt. ^ Whatever the standard be, it is always the actor and never the reus who has to carry his proof to the required height ; for, truly speaking, it is only the actor that has any duty of proving at all. Whoever has the duty does not even make out a prima facie case till he comes up to the re- quirement, and, of course, he has not, at the end of the debate, accomplished his task unless he has held good his case, and held it at the legal height, as against all counter proof. This duty, in the nature of things, here, as well as at Rome, cannot shift, except as the position of actor shifts ; it is always the duty of one party and never of the other. But as the actor, if he would win, must begin by making out a case, and must end by keeping it good, so the reuSy if he would not lose, must bestir himself when his adversary has once made out a case, and must repel it. And then, again, the actor may move and restore his case, and so on. This shifting of the duty of going forward with argument or evidence may go on through the trial. Of course, the thing that thus shifts and changes is not the peculiar duty of each party, — for that remains peculiar, i.e., the duty, on the one hand, of making out and holding good a case which will move the court, and, on the other, the purely negative duty of preventing this ; but it is the common and interchangeable duty of going forward with argument or evidence. (3.) The question of how it shall be determined whether a particular claim or defence be an affirmative one might seem very ' Bracton, fol. 239 ^ / Bonnier, Preuves, i. 51 (4 ed.), remarks :"Nos anciens autcurs, de leur c6t6. ont propos6 divers exp6dients pour r6soudre les questions douteuses. Les uns veulent qu'on tranche le diff6rend par la moiti6, ce que Cujas appelle avec raison anile judicium. D'autres proposent remploi du sort, emploi qui a kk r6alis6 effectivement en 1644 dans la fameuse sentence des bUchettes .* He adds in a note : " Par un jugede Melle qui avait fait tirer auxplaideurs deux pailles ou bUcheUes, qu'iltenait entre les doigts. Heureusement pour Thonneur de la justice, elle a 6t6 reforin6e par le parlement de Paris."
