It has not been denied that the party against whom a witness is
called may call evidence to show that the witness was not present
at the time and place alleged, or that, if he were present, he could
not have seen, or very probably could not have seen, what he claimed
to have seen. Such evidence may fail in a particular case, but it
is not therefore inadmissible. It must be evidence of a fact which
is capable of affording a reasonable presumption as to the matter
which is in dispute between the parties: See Taylor on Evidence,
12th ed. (1931), vol. 1, p. 222, sec. 316. The question is whether
the truth or falsehood of the fact of which evidence is sought to bé
given may fairly influence the belief of the jury as to a matter
in dispute (Melhwish v. Collier (1) ). As Lord Watson said in
Managers of the Metropolitan District Asylum v. Hill (2) (referring
to evidence of collateral facts, that is, facts not constituting the
matters directly in dispute between the parties), " in order to entitle
him to give such evidence, he must, in the first instance, satisfy
the court that the collateral fact which he proposes to prove will,
when established, be capable of affording a reasonable presumption
or inference as to the matter in dispute."