To William Farr 17 July [1870]
Jul 17
My dear Sir
I am very much obliged for the papers.— I feel certain that your judgment on all parts in regard to the Census is incomparably safer than mine. Firstly My impression is that it wd be better to confine enquiry to 1st cousins. Secondly, I incline to think that your second form of enquiry is the best, that is if both forms are not included; in as much as second will give the proportion out of the whole population of cousins who marry & who have children.
The object of the enquiry is to ascertain whether with mankind, consanguineous marriage within the degree of cousinship is in any way injurious, & The result of such an enquiry is almost equally important whether negative or affirmative.
In England & any part of Europe the marriages of cousins are objected to by fear their supposed injurious consequences; but this belief rests on no direct evidence. It is therefore [manifestly] desirable that this belief shd either be proved to be false, or shd be confirmed so that in the latter case the marriage of cousins might be discouraged. The returns gained if the proper queries are inserted, would show whether married cousins have in their households on the night of the census as many children, as parents who are not related; & shd the number prove fewer, we might safely infer either lessened fertility in the parents, which is more probable lessened vitality in the offspring.
If the proportional number of cousins who marry in the whole population was once ascertained, there cd exist a standard by which to judge whether the proportion, (already tabulated in some cases) of persons in asylums for the dumb & deaf the blind & insane who are the offspring of cousins is in excess of the proportion of cousin-offspring in the whole population.—
I fear I have written at too great length, but I have not felt sure, how fully you wished me to write.—
It is moreover much to be wished that the truth of the often repeated assertion, that consanguineous marriages lead to deafness & dumbness, blindness &c shd be ascertained; & all such opinion cd be easy tested, by the returns from a single census.—
It is beyond my power of filling out all the detail, to see which of your 2 forms of enquiry wd be best, if both are not included.– I could insert the words “married to—” with a blank, showing that the word cousin ought to be introduced; when this is the case.
Manuscript Alterations and Comments
1.2 parts] after del ‘the’
1.2 in regard to] interl after del ‘of’
1.2 Census is] ‘is’ above del ‘on’
1.2 Firstly] interl
1.3 Secondly…children. 1.4] bracket in margin, ink
1.4 I incline to think] above del ‘It seems to me’
1.4 that is] interl
1.4 forms] interl
1.5 in as much as] above del ‘as It’
1.5 out of the whole population] interl
1.6 have children.] after del interl ‘happen to’
1.6 have children.] altered from ‘have children at home on the night of the census.’
2.1 The object…injurious, & 2.2] crossed ink
2.1 object] above del ‘importance’
2.2 The] ‘T’ over ‘t’
2.3 of such an enquiry] interl
2.3 is] above del ‘are’
2.3 whether negative or affirmative] circled ink, line drawn to caret after ‘importance’; before del ‘The census returns will show whether cousins [‘have’ del] produce on an average as many children’
3.1 Europe] above del ‘the continent’
3.1 cousins are] ‘are’ above del ‘is’
3.1 to by] ‘by’ interl, before del interl ‘some persons’
3.2 consequences] above del ‘results’
3.2 belief] interl
3.2 direct] interl
3.2 evidence.] point over comma
3.3 It is] after del ‘only on a rather far *widely stretched [interl] drawn analogy.’
3.3 therefore] interl
3.3 belief] interl
3.3 either] above del ‘either’
3.3 proved to be] ‘to be’ after del interl ‘either’
3.3 false] above del ‘empty an idle proposition’
3.4 shd be] interl
3.4 in the latter case] interl
3.4 might] after del ‘may’
3.5 if the] after del ‘by’
3.5 proper queries are inserted] interl after del ‘query’ above del ‘supposed query inserted into the census’
3.6 show whether] after del ‘indirectly’
3.6 married] interl after del ‘in the household’
3.6 have … census] above del ‘produce on an average’
3.7 shd the number] after del ‘which’
3.8 we might] after del ‘shd be [interl] may’
3.8 either] interl
3.8 in the parents,] interl; ‘parents’ after del ‘either’, before del ‘when related’
3.8 probable] ‘e’ over ‘y’
3.9 in the offspring.] before del ‘of such consanguineous marriages.’
4.1 If the proportional…offspring in the whole population. 4.5] crossed ink
4.1 If] interl after del ‘Lastly’; ‘I’ over ‘i’
4.1 number] interl, before del illeg
4.1 of cousins] after del ‘out of the whole population’
4.1 in the whole population] interl
4.2 was once] ‘was’ above del ‘by’
4.2 exist] above del ‘be’
4.3 the dumb] ‘the’ above del ‘blind,’
4.4 the blind &] interl, above del ‘&’
4.5 of cousin-offspring in] interl; ‘cousin’ after del ‘fertility prod cousin-marriage In offspring children producing’
4.5 the whole population.] after del ‘fer’
5.1 I fear…to write. 5.2] crossed ink
5.1 but I have] ‘have’ after del ‘suppose your enquiry is far from done rather’
6.1 much to be wished] above del ‘highly highly desirable’
6.1 often repeated] above del ‘often asserted’
6.2 consanguineous] after del ‘the’
6.3 opinion] below del ‘conclusion’
6.3 by the returns] ‘by’ over del ‘in’
7.1 It is beyond … case. 7.4] crossed ink
7.2 could insert] after del ‘enclose here the first form; & I suppose you cd somehow call especial attention to’
7.3 the word] after del illeg