Sentence:  <WSD>Python</WSD>, says Bailey, is derived from Putho to putrify, and the serpent <WSD>Python</WSD> being slain by Apollo, is thus interpreted: by <WSD>Python</WSD> is understood the ruin of the waters; Apollo slew this serpent with his arrows; that is, the beams of the sun dispersed the noxious vapours, which destroyed man like a devouring serpent. 
Meaning of the word marked with <WSD> tags:  The earth-dragon of Delphi, represented as a serpent, killed by Apollo.