Darwin-Hooker Letters : Letter from C. R. Darwin to J. D. Hooker 22 October [1864]
Darwin, Charles Robert
Darwin-Hooker Letters
<p style='text-align: justify;'>To Lyell’s chagrin, CD has come round again to A. C. Ramsay’s glacial theory.</p><p style='text-align: justify;'>On primrose and cowslip, CD maintains they are good species, notwithstanding Scott’s work.</p><p style='text-align: justify;'>CD defines species by power of remaining constant for a good long time and showing appreciable amount of difference from close species.</p>