from
Bouvier's Law Dictionary, Revised 6th Ed (1856)
UNSOUND MIND; UNSOUND MEMORY. These words have been adopted in several
statutes, and sometimes indiscriminately used to signify, not only lunacy,
which is periodical madness, but also a permanent adventitious insanity as
distinguished from idiocy. 1 Ridg. Parl. Cases, 518; 3 Atk. 171.
2. The term unsound mind seems to have been used in those statutes in
the same sense as insane; but they have been said to import that the party
was in some such state as was contradistinguished from idiocy and from
lunacy, and yet such is made him a proper subject of a commission to inquire
of idiocy and lunacy. Shelf. on Lun. 5; Ray, Med. Jur. Prel. Sec. 8; Hals.
Med. Jur. 336; 8 Ves. 66; 19 Ves. 286; 1 Beck's Med. Jur. 573; Coop. Ch.
Cas. 108; 12 Ves. 447; 2 Mad. Ch. Pr. 731, 732.