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Darwin Correspondence Project

From John Lubbock   25 March 1867

25 Mar. 67

My dear Mr. Darwin

I do not know whether you have read McLennans “Primitive marriage”.1

He refers the curious practise of Exogamy to the prevalence among certain tribes of female infanticide.

I should have thought that the objection to marriage between near relations might have had much to do with it.2

Can you tell me whether we have any evidence that any animals have an instinctive repugnance to breeding in sin.

Believe me always | Very sincerely | Yours | John Lubbock

C Darwin Esq


The reference is to John Ferguson McLennan’s Primitive marriage: an inquiry into the origin of the form of capture in marriage ceremonies (McLennan 1865).
The terms exogamy (the custom of marrying outside a clan or group) and endogamy (the custom of marrying within a clan or group) were coined by McLennan (OED; see McLennan 1865, pp. 48–9, 53). McLennan surmised that female infanticide resulted in a shortage of women in a tribe, and the consequent need to capture women for marriage from other groups (McLennan 1865, pp. 138–41). For Lubbock’s later discussion of exogamy and endogamy, see Lubbock 1870, pp. 92–113.


McLennan, John Ferguson. 1865. Primitive marriage: an inquiry into the origin of the form of capture in marriage ceremonies. Edinburgh: Adam and Charles Black.

OED: The Oxford English dictionary. Being a corrected re-issue with an introduction, supplement and bibliography of a new English dictionary. Edited by James A. H. Murray, et al. 12 vols. and supplement. Oxford: Clarendon Press. 1970. A supplement to the Oxford English dictionary. 4 vols. Edited by R. W. Burchfield. Oxford: Clarendon Press. 1972–86. The Oxford English dictionary. 2d edition. 20 vols. Prepared by J. A. Simpson and E. S. C. Weiner. Oxford: Clarendon Press. 1989. Oxford English dictionary additional series. 3 vols. Edited by John Simpson et al. Oxford: Clarendon Press. 1993–7.


Discusses the practice of exogamy; asks if any animals have an instinctive repugnance to inbreeding.

Letter details

Letter no.
John Lubbock, 4th baronet and 1st Baron Avebury
Charles Robert Darwin
Sent from
Source of text
DAR 170: 56
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 5459,” accessed on 5 December 2021,

Also published in The Correspondence of Charles Darwin, vol. 15