From Thomas Bradfield   1 June 1871

Sir

The following instance of the perception in a dog may interest you. A lady I know, had a dog which used to listen very attentively to her while playing a concertina— the instrument had one note out of tune & the dog used whenever that was played to instantly begin whining—and this without any sign or instruction from the player. This incident I can assure you is a fact. The dog must have had some sense of harmony or how could it have discerned the change & marked its discernment by a whine.

Yours faithfully | Thomas Bradfield

Charles Darwin Esq