The wilds of Central America conceal the relics of an elaborate civilization now vanished, and the ruins of cities which have been without inhabitants for hundreds of years. Modern exploration holds no more exciting story than that of the attempt to unveil the secrets of these old civilizations. Dr. Thomas Gann has now for many years been on their trail. In this talk, and in another that he will give on Monday next week, he will tell some of the tales of the determined attempt that modern science is making to discover any traces that may remain of the great cities whose doom was sealed when the Spaniards entered the Now World.