It is good news that you are going to bring out a new edition of your Poultry book (237/1.

"The Poultry Book," 1872.), and you are quite at liberty to use all my materials.

Thanks for the curious case of the wild duck variation: I have heard of other instances of a tendency to vary in one out of a large litter or family.

I have too many things in hand at present to profit by your offer of the loan of the American Poultry book.
Pray keep firm to your idea of working out the subject of analogous variations (237/2.

"By this term I mean that similar characters occasionally make their appearance in the several varieties or races descended from the same species, and more rarely in the offspring of widely distinct species" ("Animals and Plants," II., Edition II., page 340).) with pigeons; I really think you might thus make a novel and valuable contribution to science.