- Stevenson with his deft, swift, adaptive spirit, and his not easily over- praised perfection in his craft, would have still done something; but he would have missed his loftiest inspiration, his style would have been far other than it is. - "My Contemporaries In Fiction", David Christie Murray.
- How can a body adapt itself to its environment unless it possess an inherent, plastic, changing, and adaptive principle? - "The Breath of Life", John Burroughs.
- In any case, however, we may work out the theory, the rate of reproductivity cannot be satisfactorily interpreted without regarding it as in great part an adaptive character. - "Herbert Spencer", J. Arthur Thomson.