Oliver Goldsmith's "Elegy on the Death of a Mad Dog"
http://www.poetry-archive.com/g/an_elegy_on_the_death_of_a_mad_dog.html
Complete text of the poem mentioned in the novel.
Sonnet: Lift Not The Painted Veil Which Those Who Live
http://allpoetry.com/Sonnet:-Lift-Not-The-Painted-Veil-Which-Those-Who-Live
Full text of the poem that inspired Maugham's title for the novel.
