From Edward Frankland   30 April 1874

My dear M^r. Darwin

I have this morning tried the experiments you suggested & now enclose specimens of the results.¹

I think the Undercliff bullfinches² have inherited a more utilitarian character than that possessed by the Kent birds. At all events my bullfinch always bites out the ovary from the primrose. Only once have I succeeded in getting a bite above the ovary & in this case the flower was in such a position behind the wire of the cage as to prevent him reaching his tit-bit. I also enclose the result of this abnormal bite.

You are quite right in supposing that the bird only presses & does not swallow the part bitten out. At all events he works the calyx gradually out of the side of his beak & lets it drop.

I never made such experiments with animals before & I am very much impressed with the result of this one. It has all ⁠⟨⁠the precision of a chemical reaction; the result of putting a primrose within its reach can be almost as certainly predicted as that of putting a plate of iron into a solution of sulphate of copper.⁠⟩⁠³

The destruction of bullfinches amongst primroses & cowslips must be enormous. My bullfinch can easily destroy 20 flowers in 3 minutes, even when they are given to him singly & he is allowed time to make the most of each, & as the amount of matter taken out of each flower is so small it is impossible to say how long it would take to satisfy him.

⁠⟨⁠about 8 lines excised⁠⟩⁠

Yours ⁠⟨⁠sincerely⁠⟩⁠| E. Frankland