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Darwin Correspondence Project

From John Medows Rodwell1   31 October 1860

Belle Vue House | Brox Bourne.

Oct. 31. 1860

Dear Sir/

I have purposely postponed writing to you again until I had an opportunity of making further observations upon my white cat. This I have now done and am able to state positively that although both her eyes are undoubtedly blue she is not in the slightest degree deaf.2 She has been several times put into a room apart with merely the door left ajar, and has always run immediately, at the summons of myself or of any of the servants, from an adjoining room in which it was impossible for her to see us. My friend Dr. Hooper of Hoddesdon3 also assures me that though he has often known cats with both eyes blue to be stone deaf he has also known them to be as fully endowed with the faculty of hearing as any others. But I hope in the course of a short time to able to report to you upon the state of a large number of white cats, as a friend of his, a lady residing not far hence, is a fancier of white cats and has a large number—of which I could only learn yesterday that some with eyes more or less tinged with pink are entirely deaf.

Now that I am speaking of cats I may mention that my late uncle the Rev. W. Kirby of Barham4 was a great Cat-fancier all his life, and that he was very careful to breed none but Tabbies, which under his care, I am afraid I must not use the word selection, as I do not know that he ever eliminated the smaller cats, though he certainly never would allow a white or Tortoiseshell on his premises, attained to a size I never saw elsewhere. He was extremely proud of his Cats, and had petted this one particular Breed for the nearly sixty years that he was Curate and Rector of Barham. From my childish days, till I became his Curate, I always recollect him with a cat on his Table, Knee or Shoulder. And I have no doubt but that careful Breeding had produced their unusual size.

It may perhaps be worth while to mention that about 1843 when I was Incumbent of S. Peter’s Saffron Hill, a large portion of the old Fleet Sewer (or River), said never to have been before opened since the days of Q. Elizabeth, was exposed to view. I then saw several enormous Rats which had been taken thence by the workmen, and upon examination they all proved to be blind and almost entirely devoid of hair, and so ferocious were they that the workmen assured me they were deterred from entering the old parts of the Sewer as the rats would unquestionably fly at them. The rats which I saw were taken out at Holborn Bridge, and as there are three arches still remaining there of an old roman Bridge some sixteen or more feet below the present surface, it is possible that those rats may have been breeding there for ages, and if like the blind cave animals you mention in C. V. of the Origin of Sps.—their progenitors lost the power of sight a 1000 years since, and lost as they would, I suppose, at the same time any great ability for migration, this would be a curious illustration of a part of your theory.5 All I can say is that some eight or ten Rats which I saw

CD annotations

1.1 I have … size. 2.10] crossed pencil
Top of first page: ‘Blind Rats—ink


Rodwell had been a friend of CD’s at Cambridge University. He graduated from Caius College in 1830 and became a clergyman and orientalist.
CD discussed the correlation between blue eyes and deafness in cats in Origin, pp. 12 and 144, where he stated that the connection was invariable. He again discussed the topic in Variation 2: 329. In Variation CD mentioned, without citing Rodwell’s case, that he had since heard of a few exceptions to the rule.
John Hooper, MD, of Hoddesdon, Hertfordshire, lived close to the village of Broxbourne where Rodwell resided.
William Kirby, the late rector of Barham, had been a leading entomologist.
CD mentioned in Origin, pp. 137–8, the blind cave-rats found in the Mammoth Cave in Kentucky as an illustration of the action of natural selection on useless organs.


Origin: On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. By Charles Darwin. London: John Murray. 1859.

Variation: The variation of animals and plants under domestication. By Charles Darwin. 2 vols. London: John Murray. 1868.


Observations on his white blue-eyed cat. There is no sign of deafness.

Apropos of ch. 5 of Origin, tells of blind rats found when a Roman bridge was excavated.

Letter details

Letter no.
John Medows Rodwell
Charles Robert Darwin
Sent from
Source of text
DAR 47: 167–8
Physical description
AL inc †

Please cite as

Darwin Correspondence Project, “Letter no. 2970,” accessed on 14 April 2024,

Also published in The Correspondence of Charles Darwin, vol. 8