Abstract
Experiments using the Warburg-Barcroft apparatus led to the following results and conclusions: (1) Two yeasts in three different media were strikingly stimulated in their respiration by minute amounts of pantothenic acid. (2) Nine other compounds (vitamins and other biologically important substances) were tested and found in all cases to have on the deficient G.M. yeast, lesser and in some cases no appreciable stimulative effect. Thiamin was the most effective of these compounds. Its action was shown to be different and in some ways antagonistic to that of pantothenic acid. (3) Liver extract (Lilly's Number 343) contains substances capable of speeding up respiration (and growth) to a much higher level than seems possible with known compounds. (4) Pantothenic acid was found to have a definite stimulative effect on fermentation by dialyzed maceration juice from yeast. (5) It likewise stimulated respiration of apple and potato tissue and indications of a similar effect on certain animal tissues were obtained.