Cartwright also invented another 'disorder', "dysaesthesia aethiopica", a disease "affecting both mind and body." Cartwright used his theory to explain the perceived lack of work ethic among slaves. Dysaesthesia aethiopica, "called by overseers 'rascality'," was characterized by partial insensitivity of the skin and "so great a of the intellectual faculties, as to be like a person half asleep." Other symptoms included "lesions of the body discoverable to the medical observer, which are always present and sufficient to account for the symptoms."