> Saws PO Sa Ly Be Exvecinentally R w £57 079-5) (0.007) = 427 reps/nr at 7 mg/ex* (P*) The two above approaches are within 26% of each other. If one extrapo- lates the experimental data fron a source of 9.6 mg/ox® to a thin source (for eoxparative purposes) the tvo zethods are within 20%,