☞ Putrefaction is a complex phenomenon involving a multiplicity of chemical reactions, always accompanied by, and without doubt caused by, bacteria and vibriones; hence, putrefaction is a form of fermentation, and is sometimes called putrefaction fermentative. Putrefaction is not possible under conditions that preclude the development of living organisms. Many of the products of putrefaction are powerful poisons, and are called cadaveric poisons, or ptomaïnes.