The Aberdeen Bestiary I was looking for manuscripts with pictures - but bonus get the translations as well http://www.abdn.ac.uk/bestiary/

Of mice

The mouse is a puny animal; its name, mus, comes from the Greek, the Latin word deriving from it. Others say mures, mice, because they are produced ex humore, from the damp soil, of the earth; for humus means earth and from that comes mus, mouse. Their liver grows bigger at full moon, like the tides rise then fall with the waning of the moon.