Thanks MATW for the results of her experiments on the inheritance of caterpillar peculiarities and would be grateful for any further observations on differences in structure or habits between silkworm breeds, or peculiarities in inheritance.
Down Farnborough Kent
My dear Madam
I cannot express too strongly my thanks for the extraordinary trouble which you have taken in the interesting experiment, of which you send me the result.— I had given up all hopes of knowing whether peculiarities in the caterpillar state were hereditary, but now the point is amply proved: there is indeed a wide difference between a probability, however high & such an experiment as you have made.—
I am, also, much obliged for the information about the S. French caterpillar breeds; I was not aware the differences were so great.
If it would not be asking too great a favour, I sh
Pray accept my most cordial thanks, & believe me with much respect, | Your's sincerely obliged | C. Darwin
- f1 1194.f1The date is based on the broad mourning border characteristic of the stationery used by CD in 1849.
- f2 1194.f2See CD's request in his letter to M. A. T. Whitby, 2 September . He cited the results in Variation 1: 302.
- f3 1194.f3Whitby 1848 mentions cocoons from eggs imported from Bordeaux and Poitiers. A table indicates that these cocoons gave 1
oz. of reeled silk, whereas the equivalent weight of cocoons of English and Italian species yielded 3 4 oz. and 1 oz., respectively (pp. 56–7). 1 4
- f4 1194.f4See letter to M. A. T. Whitby, 2 September , in which CD asked about the possibility of conducting an experiment to see if ‘frales’ would reproduce their kind. The original manuscript reads ‘Frates’, but from CD's letter of 2 September  it is clear that this is another instance of his unintentional crossing of an ‘l’.
- f5 1194.f5According to Variation 1: 303, ‘Cocoons are sometimes formed, as is well known, entirely destitute of silk, which yet produce moths; unfortunately Mrs. Whitby was prevented by an accident from ascertaining whether this character would prove hereditary’.