[Darwin refers to remarks made by his correspondent on the subject of On the Origin of Species.² He writes: ‘I am very glad indeed to read remarks made of a man who possesses such varied and odd knowledge’.³ Darwin continues his letter with discussion of a manuscript on proportions of the sexes at birth that W. R. Greg has sent along for review⁴ but returns to commentary of On the Origins of Species. He notes his own ‘remarks on mankind are superficial, and given merely as some sort of standard for comparison with the lower animals’. He closes his letter remarking, ‘I am quite delighted that my book interests you enough to lead you to read it with such care […]’]