The Effects of Habit and Use of Parts

Some naturalists have maintained that all vary tions are connected with the act of sexual reproduction. But this is certainly an error. Under culture, as a single bud out of many thousands produced year after year on the same tree under uniform conditions, has been known suddenly to assume a new character. Changed habits produce an inherited effect and so do increased use or disuse of parts. Not one of our domestic animals can be named which is not in some country. Drooping ears may be due to disuse of muscles from being seldom much alarmed.