ConclusionsA synthetic ration containing the 6 crystalline members of the B group which will support growth and reproduction in the rat was found wholly inadequate for the hamster. The addition of para-aminobenzoic acid and inositol increased the survival time of the hamster. A definite need for biotin was shown, the animals growing excellently and reproducing when it was included in the ration along with the 8 members of the B group including inositol and para-aminobenzoic acid. On the complete sjrnthetic diet including biotin, inositol, and para-aminobenzoic acid, vitamin C and nicotinic acid are not required by the hamster.