An Etymological Dictionary of the German Language/Annotated/Milz
Milz, feminine, ‘milt, spleen,’ from the equivalent Middle High German milze, Old High German milzi, neuter; from the High German form are derived the Romance cognates, Italian milza, Spanish melsa, ‘spleen.’ Corresponding forms are found in Old Icelandic milte, neuter, Anglo-Saxon milte, neuter and feminine; English milt and Dutch milt signify both ‘spleen’ and ‘soft roe.’ The cognates are probably connected with the Teutonic root melt (see Malz), ‘to soften, melt,’ “with respect to the properties ascribed to the spleen of manufacturing, decomposing, and liquefying the various humours of the body.” The term Milz is found in Teutonic only; so too Hand, Finger, Daumen, Zehe, Leber, &c. The names of other parts of the body, such as Herz, Niere, Fuß, Arm, Rippe, have, however, a history that can be traced farther back.