The products of the transmutation of mercury by fast (Li+D) neutrons were investigated. Three radioactive gold isotopes were found to be formed by the n-p reactions: 65-hour Au198, 78-hour Au199, and a new unassigned electron emitter with a period of 48 min. Three radioactive platinum isotopes were observed and attributed to n-α reactions in mercury: 29-min. Pt199, 19-hour Pt197, and a new activity with an 80-min. half-life. The latter period was also observed in deuteron and fast neutron bombardment of platinum, but was not found in slow neutron irradiation of platinum. Radioactive mercury isotopes with 43-min., 25-hour, and 50-day periods were observed in the fast neutron irradiation of mercury. The 43-min. and 25-hour activities were also formed by bombarding platinum with α-particles. Difficulties in the assignment of the 80-min. Pt and the 43-min. and 25-hour Hg activities are discussed.