example, there is the well-known case
of the Harvard professor who was apparently sane on all other matters,
yet believed himself to be possessed of glass legs. Had this man in
wanton anger struck and killed another, his "glass leg" delusion could
not logically have availed him. If, however, he had struck and killed
one who he believed was going to shatter his legs it might have been
important. The illustration is clear enough, but its application
probably involves a mistaken premise. If he thought he had glass legs
his mind was undoubtedly deranged--whether enough or not enough to
constitute him irresponsible or beyond the effect of penal discipline
might be a difficult question. The generally accepted doctrine is, that
if a man has a delusion concerning something, which if actually existing
as he believed it to be would be no excuse for his committing the
criminal act, he is responsible and liable to punishment; but, as Bishop
well says:

"This branch of the doctrine should be cautiously received; for delusion
of any kind is strongly indicative of a generally diseased mind."

The new test to determine responsibility will recognize, as does the
law of Germany, that there can be no criminal act where the free
determination of the will is excluded by disease, and that the capacity
to distinguish between right and wrong is inconclusive. It may
perhaps have to take a general form, leaving it to a lay, or a mixed
lay-and-expert jury to say merely whether the accused had a disease
of the mind of a type recognized by science, and whether the alleged
criminal act was of such a character as would naturally flow from that
type of insanity, in which case it would seem obviously just to regard
the defendant as partially irresponsible, and perhaps entirely so.
Possibly the practical needs of the moment might be met by permitting
such a jury to determine whether the defendant had such a knowledge of
the wrongful nature and consequences of his act and such a control over
his will as to be a proper subject of punishment.* This would require
the jury to find that the defendant had some knowledge of right and
wrong and the power to choose between them. In any event, to render
the accused entirely irresponsible, his act should arise out of and
be caused solely by the diseased condition of his mind. The law, while
asserting the responsibility of many insane people, should recognize
"partial" responsibility as well.

*See Stat