It isn’t every day that something like this happens. Researchers using spectral imaging techniques have uncovered the commentary within a text known as the Archimedes Palimpest. Medieval recyclers seem to have thought this pagan work unworthy of preservation, because they just scrubbed it off and re-used the manuscript. The original is on the left, the revealed text on the right.
The comments are provisionally attributed to Alexander of Aphrodisias, and read as follows:
For as “foot” is ambiguous when applied to an animal and to a bed, so are “with feet” and “without feet”. So by “in species” here [Aristotle] is saying “in formula”.
For if it ever happens that the same name indicates the differentiae of genera that are different and not subordinate one to the other, they are at any rate not the same in formula.
It might seems like a lot of hoo-ha for a couple of lines of text, but consider this: if this can be discovered by these methods, who knows what else is hidden in the pages of some of the venerated tomes in places like the Vatican, British Library or the Library of Congress? If you’ve ever read Umberto Eco’s The Name of Rose – or even seen the film – you’ll know how much influence Artistotelian interpretation has had.