collateral facts

COLLATERAL FACTS evidence. Facts unconnected with the issue or matter in 
dispute. 
     2. As no fair and reasonable inference can be drawn from such facts, 
they are inadmissible in evidence, for at best they are useless, and may be 
mischievous, because they tend to distract the attention of the jury, and to 
mislead them. Stark. Ev. h.t.; 2 Bl. Rep. 1169; 1 Stark Ev. 40; 3 Bouv. 
Inst. n. 3087. 
     3. It is frequently difficult to ascertain a priori, whether a 
particular fact offered in evidence, will, or will not clearly appear to be 
material in the progress of the cause, and in such cases it is usual in 
practice for the court to give credit to the assertion of the counsel who 
tenders such evidence, that the facts will turn out to be material; but this 
is always within the sound discretion of the court. It is the duty of the 
counsel, however, to offer evidence, if possible, in such order that each 
part of it will appear to be pertinent and proper at the time it is offered; 
and it is expedient to do so, as this method tends to the success of a good 
cause. 
     4. When a witness is cross-examined as to collateral facts, the party 
cross-examining will be bound by the answer, and he cannot, in general, 
contradict him by another witness. Rosc. Ev. l39.