To Henry Doubleday   [before 5 February 1857]¹

– have bred all these varieties from the same set of eggs, so that there can be no doubt that they are all the same species?² I trust & think that your kindness will make you forgive my writing so long & troublesome a letter.— I can assure you, that in so far as giving me knowledge, which I value, your note will not have been thrown away upon me.

Pray believe me | My dear Sir | Your’s truly obliged | Charles Darwin

I must express my admiration at the skill with which your Box was packed up; & must confess, until I read your letter, I was somewhat dismayed to think how I sh^d. ever return it half so neatly!

I think there is no difference in the Peronias except in the wondrous differences of colour, & somewhat in size.— I presume that there is no rule of any of the coloured vars. tending to be smaller or larger.³