Production of Cl. welchii Toxin in Peptone-free Medium

Cl. welchii was grown in a medium free from peptone or other substances of large molecular weight. Toxins were consistently produced which were equal to or more potent than those produced in glucose peptone beef infusion broth. The pH of the culture media did not fall below 6.0. This may in part be responsible for the higher potency of toxin obtained in this medium. The basal medium alone did not support growth; when it was supplemented with pantothenic acid, pimelic acid, nicotinic acid, riboflavin, or liver-extract, there was a marked increase of growth and toxin-production.