“O Heaven, were my whiskers neglected!”

Murr in love:

E.T.A. Hoffmann, The Life and Opinions of the Tomcat Murr, trans. Anthea Bell (1999).

Also from this novel
“Scholarly voracity” : “My little right paw” : Reading and writing in the dark

[From the notes to this edition: “Ovid’s De arte amandi and Manso’s Art of Love: Ovid’s famous verse work on the art of love is properly entitled Ars amatoria. Johann Kaspar Friedrich Manso (1759-1826) wrote a work thus entitled, and published in 1794, which is mocked by Goethe and Schiller in their Xenien.”

The play is As You Like It, III.ii. Signs of a lover: “A lean cheek, which you have not; a blue eye and sunken, which you have not; an unquestionable spirit, which you have not; a beard neglected, which you have not.”]