Page:Divine Selection or The Survival of the Useful.djvu/92

 itself, and is developed to its fullness by the sense-faculty using it in nature.

The eye of the Cave-fish is sightless, not because of the absence of the essential sense-faculty, but it is due to the absence of the plane of reaction that use in nature provides, and has, following the law of non-use, suffered atrophy.

That both the eye and the ear are developed alike from the sensitive hair sac, does not indicate that the senses are derived from one, that of feeling. It only reveals that the eye and the ear are developed from the same material substance and planes. It only argues that the faculty of seeing uses the same matter to form the organs of the eye as the faculty of hearing uses to form the organ of hearing. Because the whole human body is made of protoplasm does not argue in any degree that all its faculties are derived from one. Because a house and a church are built of brick does not indicate that both were built by the