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Darwin Correspondence Project

From George Tollet1   [10 May 1839]

[Betley Hall]

1st It will not I think keep constant; it will tend in appearance to one parent or the other but will more commonly shew in individuals an evident admixture of both— In Pigs some would be more like the Chinese others more like the common breed—but all would shew the Cross in some degree. The Chinese character being probably the older race would prevail. As before stated the progeny will shew the admixture for some generations even under the greatest care taken in matching them—

2nd There is little doubt but by great care in selecting for several generations the character would become more permanent, but for a long time the characters of the different varieties of the first cross would frequently occur—but it must have been by a long perseverance that the different varieties or Races have been formed—

Thirty years ago in order to get a large breed of Fowls I crossed once with the large long-leg’d Malay-breed Having endeavoured to breed Fowls with compact bodies and short legs from the time of the first Cross yet the long-leg’d character of the Malay fowl—together with a tenderness of the feet from cold is frequently breaking out This year a Hen of my sort was crossed with a particularly handsome short leg’d Dutch Fowl belonging to my Son But the Malay blood shewd itself most pointedly in two young Cocks the produce of this Cross: So that it is difficult to say how many generations would be requisite form a mixed Race into a permanent Variety

3 I think a new character appearing in a male & female of an established Race would probably be made permanent after successive generations by carefully selecting and breeding from those which happen to possess the character in question. To effect this after a certain time the choice out of a considerable number would be desirable—

4 If the Australian Dingo is an older or aboriginal Breed the Cross from the Spaniel Bitches would I think more resemble the Australian than the Pug: and would be most persistent under similar circumstances in successive generations—

What has been said of the Malay Fowl—I think shews it to be much nearer the aboriginal breed—probably from proximity to the Jungles of India

5 If you can suppose such a Cross to be fertile I think the character of the Fox would prevail for a great length of time

6 I should be inclined to think they would be more apt to take after the Father than the Mother but it would be by no means certain

(8) I think every cross has a tendency to make the offspring prolific But if the Chinese Pig were crossed with a race less prolific, the offspring would most likely not be so prolific as the original Chinese tho more prolific than the race with which it was crossed

Breeding in and in as it is called has a manifest tendency to decrease the prolifickness of Animals

Sir John Sebright many years ago published an interesting little Book on this subject.2 I have mislaid it or I would have referred to it

(9) No experience

10 No experience

11 I should suppose by means of the Male. This I understand is generally the case in breeding Hybrid Canary Birds

13 — No experience

14 No experience but I should think it would be a mere chance

15 No experience

16 In Bulls it has a tendency to weaken the masculine form and I suspect also the virility— I have seen very high bred Bulls that had lost many of the characteristics of the Males It was thought an improvement but it was found to be an imperfection, and the more masculine appearance was again preferr’d— The same circumstances happen’d in the breed of Sheep—

Breeding in and in or closely in an improved Stock greatly lessens the fertility of Cattle. Mr Mason of Chilton sold a high bred Durham Heifer for 1000 Guineas upon a warranty that she was to produce 3 Calves—or the bargain was to be off— She was too high bred to do this—some of the defects of inter-breeding might be lessened in a large stock by judicious selection—

(17) I think timidity—ill temper &c. are hereditary—and I should not chuse to breed from animals that had those or similar defects

18 No experience

[19.] No exp

[20.] No experience

[21.]In crossing Cattle which may be very advantageous under certain circumstances, the Agriculturist would never by choice go on breeding from Mongrels. In Dairy Cattle crossing may be generally advantageous and the choice would be of breeds yeilding either in quality or quantity or both the best return of Milk Butter & Cheese The Holstein, Dutch or Holderness Cow is large & gives a large quantity of Milk—but not of rich quality The Ayrshire Cow is smaller and gives a good return of Milk of better Quality. If from circumstances a smaller animal with better Milk were desirable the Dairy Farmer would put an Ayrshire * Bull to his Yorkshire short Horned Cows But to carry on the breed he would not use a Bull of the mixed breed but would go on with an Ayrshire Bull till his object was attained— If he afterwards wished for larger size he would use a Yorkshire Bull & so keep changing to suit his purpose

The Alderney Cow is still smaller than the Ayrshire & the Milk is still richer. From one or other of these crosses, (which may all be reckoned short-horned varieties the best sort of milking Cow may be obtained

N.B The first Cross generally gives so much vigour that the produce is apt to be superior to either of the Parent breeds.

N.B* where the choice can be had it is always better to have the Cows of the larger & the Bull of the smaller Breed—

CD annotations

scored brown crayon
scored brown crayon
At head of questionnaire: ‘Mr George Tollet | Betley Hall | 10th of May 1839—’ pencil


See letter from Richard Sutton Ford, 6 May 1839, n. 1. Tollet’s replies are written on the printed questionnaire in the wide margin CD provided for the purpose. They are the only extant replies actually written on the questionnaire (Freeman and Gautrey 1969).
Sebright 1809. CD refers to this work in Notebook C: 273. His copy in Darwin Library–CUL is heavily annotated.


Notebook C. See de Beer 1960; de Beer and Rowlands 1961; de Beer, Rowlands, and Skramovsky 1967; Notebooks.

Sebright, John Saunders. 1809. The art of improving the breeds of domestic animals. In a letter addressed to the Right Hon. Sir Joseph Banks. London.


Replies to [Questions about breeding].

Letter details

Letter no.
George Tollet
Charles Robert Darwin
Sent from
Source of text
DAR 186: 51
Physical description
Amem 7pp †

Please cite as

Darwin Correspondence Project, “Letter no. 510,” accessed on 6 December 2021,

Also published in The Correspondence of Charles Darwin, vol. 2