Thanks CD for Descent.

Sends a copy of his oratio inauguralis on De harmonie van het dierlijke leven [1848] in which he espoused evolution, but did not see the influence of natural selection.

Comments on FCD’s 1848 work [see 7582] in which he came near to anticipating CD.

Comments on FCD’s paper [on action of the eyelids, see 7203]. Asks about contraction or dilation of the iris due to emotional states, illness, or prostration.

Answers to CD’s queries will take time. CD may not be aware of the influence of accommodation on the diameter of the pupil of the eye. Parrots, for example, contract or dilate the pupil independently of amount of light [see Expression, p. 304]. Sends his book on the subject [On the anomalies of accommodation and refraction of the eye (1864)].