"But we cannot succeed in keeping sleep free from stimuli; just as Mephisto complains of the germs of life constantly stirring"

    A reference to Part I of Faust, a metaphysical tragedy by German polymath Johann Wolfgang von Goethe (1749-1832).  In Goethe’s play the demon Mephistopheles, who speaks and acts on behalf of Satan, notes resentfully the endless regeneration which prevents life on earth from ever being truly annihilated:

The air, the water, and the earth

A thousand germs and buds brings ever forth

 

Online text of Faust: The First Part of the Tragedy, (first published 1808)