without referring to it as a confession, or to the signed 
statement, unless, or until, the examiner desires so to 
bring it in. 
7. Testimony on matters requiring expert opinion 
necessitates the qualifying of the witness, and the basis 
of this qualification should be definitely determined. 
A scientific expert usually tells the attorney what he has, 
and submits a list of questions, then together they decide 
upon the ones to use. The materials upon which expert 
testimony is based must, of course, first be placed in evi¬ 
dence by the witness who found them. In respect to 
finger prints, for example, a forest officer should testify 
that he found the given article, suspected it to contain 
such prints, developed them, and later secured the prints 
of the suspect. But no nonexpert witness will be allowed 
to testify as to similarities or any other matter of opinion 
or conclusion. If it has not been possible to get expert 
evidence as to identification, the matter will have to be 
left there, for the jury to study and draw their own con¬ 
clusions, except that the attorney or other person con¬ 
ducting the prosecution can take up the subject later in 
his argument to the jury, and, if he has not been able to 
bring on an expert witness to testify to such matters, he 
may then draw out what would otherwise have been 
covered by them. This, of course, is a less effective 
method than to have the identification covered by actual 
testimony. 
8. Guard, as far as possible, against opinions by your 
own witnesses that the accused was drunk when the 
offense was committed or that he is a monomaniac (that 
is, in respect to setting fires). These constitute possible 
defenses which will be seized by the opposing side. If on 
their own motion they set up such a defense, every means 
should be used to counteract its effect on the jury, either 
by impeaching such testimony or by strengthening ele¬ 
ments of the case showing moral responsibility. When 
such a defense is probable, prepare for it beforehand. 
A case against a female defendant, or anyone with a 
bodily infirmity, must be exceptionally strong, since 
juries are easily swayed by sympathy in such cases. 
