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Darwin Correspondence Project

From Richard Frean   17 February 1863


Feb 17th 1863.


Dr Sir

I am much interested in the subject of your book on the “Origin of Species”1 & this must be my apology for addressing you   At the time of its appearance I was a Medical Student in London, & much attached to the study of Geology, general Natural History &c, & more particularly at that time—Animal and Vegetable Morphology.2

It is not surprising therefore that I was obliged to accept your Hypothesis as the only satisfactory explanation of all that is so perplexing & mysterious in these latter subjects. Of course other considerations,—especially the inhabitants of the Galapagos Archipelago & other facts in the Geographical distribution of Animals & Plants contributed to this result.

The remarkable unsymmetrical structure of the Sole, Turbot & other Fishes of the Pleuronectidæ had attracted my attention & appeared a strong argument in its favor.3

The Teats & Lacteal glands of the Mammalia present a difficulty   I cannot imagine how these can have been developed by ‘Natural selection’   I am anxious to know the views of others on the subject.

The degeneration of civilized man appears to be a necessary consequence of your hypothesis—if the following reasoning is correct. Man’s organs of locomotion, hearing smell, taste & sight were modified & maintained by natural selection when the life of the individual & the existence of the species depended upon their efficientcy. After a time his more perfect hand & superior reasoning powers gave him ascendancy over kindred forms in the struggle for life.

Civilization ensues; the strong protect the weak, machinery is used for locomotion, for defence against natural enemies, for preparing food &c &c, & robust health & acute senses are no longer the conditions of the life of the individual & the perpetuation of the species. They must therefore necessarily decay. The consideration of cultivated plants & domesticated animals will prove that variations of scructure are greatest when the plant or animal is placed under unnatural conditions. Civilized Man is thus placed. His various organs &c. will be liable to great variations & since natural selection cannot act in preserving the good & eliminating the bad, They must all ultimately be injurious for those which at first are beneficial, will by exaggeration become so.

This process of degeneration may have a limit for it may be supposed that natural selection will act when variations of structure interfere with a prolific reproduction, yet it is difficult to see how this principle can do so when variations are large & frequent. If these deductions are correct they are of practical importance. The future object of Medical Science will be the prevention rather than the cure of disease; & this will be accomplished by subjecting the body as far as practicable to its former conditions. A more natural diet, thin clothing, a large amount of exercise &c will be some of the conditions of health & physical enjoyment. Extremes will meet for the highest civilization will approximate the savage state.

I am | Dr Sir &c | R F

C. H. Darwin Esq. M.A


Frean later trained as a surgeon at the Middlesex Hospital, London, and qualified in 1871, but no record of his earlier medical studies has been found.
Pleuronectidae is the family of dabs, halibuts, and righteye flounders. During development the left eye migrates to the right side of the head, allowing the fish to lie on the ocean bottom on its left side, with both eyes facing up.


Discusses his reading and understanding of Origin.

Please cite as

Darwin Correspondence Project, “Letter no. 3993F,” accessed on 20 September 2020,

Also published in The Correspondence of Charles Darwin, vol. 18 (Supplement)