From William Henty 20 February 1868
3 Montpelier Villas | Brighton
20 Feby 68
Sir/
In response to your letter in the Agricultural Gazette of the 15 Feby permit me to state that I have for some time had my attention drawn to a theory or principle on the balance of the sexes which bears on your enquiry & which may perhaps tend to illustrate the subject1
I addressed a note to the Agl. Gazette a few weeks ago drawing attention of graziers & farmers to what seems to be the law of nature, by which the sex of the progeny is determined, which if clearly understood & confirmed will enable the breeder to arrange what proportion of either sex his stock shall produce2
The principle is simply that nature which takes the utmost pains to secure the reproduction of her creations will cause the first products of generation to follow the sex of that one of the parents whose constitution is oldest (from age or infirmity) & is therefore likely to die first
Having seen this principle stated above 30 years ago I have amused myself in tracing its results in man & animals & with almost invariable certainty.
For instance the known fact that males of the human species predominate in the proportion of 18 to 17 over females which is quoted by Paley & others as a special arrangement by Providence to provide against the casualties of war &c may by this rule be easily accounted for as on an average of marriages men largely exceed their wives in age3
Throughout the families of my acquaintance I can remember but one decided failure in its application. In others there have been apparent failures but explained by the after knowledge of facts in their physical condition e.g. one young wife of an elderly person produced a daughter but it turned out she had an open ulcer in her leg In two similar cases the wife had a family of daughters, the cause being that whilst in childbearing she was in delicate health but after that period they recovered their former strength of constitution
When the folks on the Stock Exchange were betting about the sex of the expectant offspring of Louis Napn. I stated my opinion without hesitation that it would prove a son.4 In my own case I applied this rule successfully when putting a favorite mare to a blood horse—& I have known a friend exclaim—against his ill luck in always having a bull calf when he had permission to send a cow cost free to a very celebrated old bull—whereas if he had sent a cow older than the sire he would doubtless have had a heifer calf
One apparent exception was pointed out by a gentleman—a large breeder, in the fact that the first calf of a young heifer is generally a cow calf
This I attributed to the circumstance that, the cows running indiscriminately (in Australia) with the bulls the heifers took the bull before they had themselves arrived at full maturity & whilst their constitution was therefore weaker than that of the male.
The authority in which I found the statement of this theory was a volume of lectures on Political Economy by J. Bryan Esqre delivered before the Royal Society of Dublin about 34 or more years since5
I have heard also that Mr. Coombe6 has made allusion to it
I hope shortly to make fuller reference to these authorities when I am able to pay a visit to the British museum & to communicate any further information if deemed by you of sufficient interest to the particular subject of your present enquiry
I remain | Sir | Faithfully yours | Wm. Henty
Chas Darwin Esqre | &c &c
Footnotes
Bibliography
Paley, William. 1785. The principles of moral and political philosophy. London: R. Faulder.
Summary
Has read CD’s inquiry about proportional numbers of males and females born to domestic animals [see 5863] and outlines his theory regarding the factors determining the sex of offspring.
Letter details
- Letter no.
- DCP-LETT-5900
- From
- William Henty
- To
- Charles Robert Darwin
- Sent from
- Brighton
- Source of text
- DAR 166: 181, 183
- Physical description
- ALS 6pp
Please cite as
Darwin Correspondence Project, “Letter no. 5900,” accessed on 28 March 2024, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-5900.xml
Also published in The Correspondence of Charles Darwin, vol. 16