Darwin-Hooker Letters : Letter from Darwin, C. R. to Hooker, J. D. on 27 June 1854 : 1r
'Darwin, C. R.'
Darwin gives his definition of 'highness' and 'lowness' as 'morphological differentiation' from a common embryo or archetype. Hooker's view, with which Darwin agrees when it can be applied, is the same as Milne-Edwards', i.e., the physiological division of labour. There is little agreement among zoologists and Darwin admits his own lack of clarity.