Source : Webster's Revised Unabridged Dictionary (1913)

Fermentation theory \Fer`men*ta"tion the"o*ry\ (Med.)
   The theory which likens the course of certain diseases (esp.
   infectious diseases) to the process of fermentation, and
   attributes them to the organized ferments in the body. It
   does not differ materially from the accepted germ theory
   (which see).