Following the study of the catalytic hydrogenation of benzo [~] pyrene,~ with the object of investigating the carcinogenic and anti-carcinogenic properties of the products, a similar investigation of the catalytic hydrogenation of dibenz [a, h] anthracene was undertaken, with the same objective. A preliminary report of the biological activity of some of the hydrogenation products of dibenz [a, h] anthracene has been p~ blished.~
