Fig. 13. Skulls of three Rabbits, mother (3 and 3a), father (1 and la) and son (2 and 2a). From Publication No. 114, Carnegie Institution of Washington, by permission.

What has already been accomplished in the study of heredity gives us a hopeful outlook for the future. We are gaining a fuller knowledge of its processes, and a knowledge of processes is a first step toward their control.