“ When in making a statement, taking an oath, &c., a person qualifies that statement in his mind, or withholds some fact, word or expression which, if expressed, would materially alter the effect of his statement or oath, such qualification is termed a “ mental reservation,” or, in the technical language of casuistry, “ mental restriction ” (see Liguori) . The system of providing special tracts of land exclusively for the tribes of American Indians, adopted in the United States of America and in Canada, is known as the Reservation system, and such tracts are styled Indian Reservations. ”