396 PRICE v. TYSON.—3 BLAND.

admission of the truth of which, or the proof of the truth of which
is necessary to entitle him to relief. Cooth v. Jackson, 6 Ves. 37.
And after having given, in all respects, such an answer as the bill
requires, the defendant may, and indeed, always should go on, by
way of further answer, to state all matters in bar, or by way of
avoidance which he may make available as a defence against the
plaintiff's claim; for it is a well established rule, that a party can-
not be allowed to offer evidence to sustain any allegation which he
has not made and relied upon in his bill or answer. Waley v. Nor-
ton, 1 Vern. 483: Sidney v. Sidney, 3 P. Will. 276; Clarice v. Turton,
11 Ves. 240; Smith v. Clarke, 12 Ves. 480. As where to a bill for a
specific performance, although the defendant is bound to answer
fully as to the agreement relied on by the plaintiff; yet he may, by
waj of avoidance, and as a defence against the claim presented by
the bill, set forth the agreement which was really entered into be-
tween them; and the plaintiff may, if he admits the truth of the
defendants' answer, amend his bill and take a decree accordingly
upon the discovery and confession of the defendants. But having,
by his amendment, virtually waived all claim founded on the con-
tract as set out in his original bill, he cannot be allowed to offer
proof to sustain such claim after the amendment has been made.
Lindsay v. Lynch, 2 Sch. & Lefr. 9.

The object of a discovery from the defendants for the purpose of
giving relief here, is to obtain evidence in relation to the subject
*in controversy, either because the plaintiff cannot other-
399 wise prove the tacts or in aid of proof. And hence the an-
swer should, in all cases, not only disclose the truth, but the whole
truth; it should not only speak the truth in relation to a particular
circumstance, or part of the case; but the whole truth in regard to
all the component parts of that case which is the subject of litiga-
tion between the parties. For, otherwise, if the plaintiff were al-
lowed, by special interrogatories, to cull from the defendants'
knowledge of the whole matter in dispute only such particular
facts as suited his purpose; and the defendants were rigidly con-
fined to the making of only such answers as such interrogatories
would warrant, the truth of the case might be most grievously dis-
torted and the whole course of justice perverted. This as to a bill
for relief as well as discovery, is sufficiently evident.

The object of the discovery prayed by this bill is not, however,
to enable this Court to give relief, but to aid a Court of common
law in giving it. This plaintiff, it appears can only obtain relief
from a Court of common law according to the facts which he may
be able there to establish.

It is the duty of a Court of justice to act only according to the
whole truth; it cannot allow any pertinent and legal testimony to
be withheld or garbled; and it is of no kind of consequence
whether the proofs are brought before it by means of its own pro-