Sentence:  He [Benjamin Ridge] professes to have reduced the examination of the tongue for purposes of diagnosis to a system. ... [H]e describes the dyspeptic, febrile, inflammatory, cerebral, rheumatic, pulmonary and cardiac tongue, &c., and he argues that the nature and seat of diseases may be detected and discriminated by cultivating this new science of <WSD>glossology</WSD>, even when neither the other physical or rational signs are suffcient for a true diagnosis. 
Meaning of the word marked with <WSD> tags:  The diagnosis of disease by examination of the tongue.