Sir,—

I should be very much obliged to you or to any of your readers, if they would have the great kindness to refer me to any observations which may have been published on the proportional number of males and females born to our various domestic animals, such as cattle, sheep, horses, dogs, poultry, ducks, &c. I presume that this point has often been attended to, but I am at a loss where to search, and should be grateful for any reference or for any unpublished facts.²

Sir, your obedient servant,| Charles Darwin

Down, Bromley, Kent, S.E., Feb. 11.