THE available literature contains only one record of the urinary excretion of the vitamins of the B complex by normal infants during the first week of life. Neuweiler1 measured the twenty-four hour excretions of thiamine by babies 1 to 10 days old and obtained single values at the ages of 12, 14, 15, 18, 19, 23, 46, 63 and 112 days. He observed that the excretion of thiamine by the nursing child is small, but is somewhat higher during the first four or five days of life than later. He observed also that an oral supplement of thiamine to the baby was well absorbed, for it appeared in the urine immediately. When an injection of 25 mg. of thiamine hydrochloride was given the mother shortly before delivery, the urinary excretion of the infant showed relatively small increases in thiamine concentration, which declined after three days. Neuweiler expressed the opinion