ases of
lunacy does not rest chiefly with the medical expert. In cases of
doubtful insanity the decision is to be given not by the Doctor but by
the court of justice. Except on very special occasions, as when a
physician is appointed on a committee or commission of inquiry, he
appears before a court either as an ordinary witness, stating what
facts have fallen under his personal observation; or as an expert,
explaining the received opinion of medical men with regard to cases of a
certain class. Even though he feels convinced that the culprit or the
patient is as mad as a March hare, the physician cannot expect that his
statement to that effect will be received as decisive. It is for the
judge to instruct the jury what kind or degree of insanity will excuse a
culprit from legal punishment, or will disqualify a person from
testifying as a witness, or from being a party to a civil contract in
certain cases; and it is for the jury to decide whether, in the case in
hand, the fact of such insanity exists or not. In criminal cases, the
jury pronounces on the double question, whether the accused did the act
charged to him, and whether he has been juridically proved to have been
accountable for the act under the laws as expounded by the judge.

1. To come to a decision on this double question, the jury might need to
hear the facts stated which the physician has personally observed, and
of which he is summoned to be a sworn witness. In such a situation all
that is required of the Doctor is that he shall give a most faithful
and intelligent account of the facts.

It would disgrace his standing in society if any fault could be found
with his testimony; and, as a sworn witness, he is bound in conscience,
like any other witness, to state the truth, the whole truth, and nothing
but the truth. This is always the case when the purpose of the inquiry
is the discovery of the sane or insane condition of a person's mind. But
if the inquiry concerns the performance of the guilty act, the
commission of the crime, many States of the Union, as explained before,
consider the Doctor's professional secrets as privileged, just like
those of the lawyer and the clergyman; i.e., the Doctor must not use
against his patient any knowledge he has become possessed of while
acting as his medical adviser.

2. When the physician appears before a court or commission as an expert,
he is expected to give the views of the medical profession upon
hypothetical c