He also revised and enlarged the "Seisetsu Naika Senyo" (Selected Points of Western Theories on Internal Medicine) that had been translated by his adoptive father Genzui, and invented new characters for describing medical terms (he did not apply some Chinese characters which had already existed to new concepts, he practically made new characters [although those look like Chinese characters even to Chinese and Japanese]) including '腺' which refers to secretor and '膵' which refers to pancreas; this was one of Genshin's epoch-making achievements.
また、養父玄随の訳した『西説内科撰要』の増補改訂版を作成し、分泌器官に用いる「腺」や膵臓の「膵」の字など医学用語を作成（字を発見し当てはめたわけではなく造字した）したのも玄真の功績の一つである。