The averment in the complaint that the tax-sale certificate had been duly assigned to the plaintiff is essential to his cause of action, and is therefore a traversable averment. The appellant traversed it “ upon information and belief.” The only question necessary to be determined on this appeal is whether a traverse in that form is allowable. Except in those special cases in which the defendant is conclusively presumed to -have positive knowledge as to the existence or non-existence of a fact alleged in the complaint, we have no doubt that the defendant may interpose a denial in this form. He may have information which satisfies him how the fact is, and yet he may not have any actual, positive knowledge thereof. In such case he can deny in no other form. He cannot deny' positively, because he does not know positively that such a denial would be true. He cannot deny knowledge or information sufficient to form a belief, because he has formed a belief on sufficient information. The only mode in which he can answer truly is to deny upon information and belief. A denial in this form, in a proper case, is a compliance with sec. 2655, B. S., otherwise the provision in sec. 2666, which allows any pleading to be verified by an affidavit that, as to matters therein stated on information and belief, the affiant believes it, to be true, would be meaningless and inoperative in respect to the verification of an answer.
The answer in the present case contains a sufficient denial of a material fact alleged in the complaint, and puts the plaintiff to his proof of such fact. Failing to prove it, or *236the same being disproved by the defendant, the action fails. Of course such an answer is neither sham nor frivolous.
We do not consider the other portions of the answer.
By the Court.— Order reversed.