been reported to be a strong inhibitor of the growth of Streptococcus faecalis R. 3 but not of Adenocarci-nomu 755.* The closely related compound having an hydroxy group in place of the 7-amino group has been prepared as described below. It produces a 65% reduction in the growth of L. casei at a concentration of 0.005 mg./ml. 6 The effect can be reversed by pteroylglutamic acid or adenine. The results of screening against various tumors are to be ...