Through Mill, Lord Amberley met Douglas Spalding, a lawyer by profession and amateur biologist whom he employed as a tutor for his sons. Amberley encouraged him to continue his research on imprinting at his home, although his guests were terrified to see chickens roaming around the drawing-room and library. Spalding suffered from tuberculosis and was thus considered unfit for marriage. Lord Amberley felt that there was nevertheless no reason to condemn Spalding to celibacy and, after a discussion with his wife, allowed them to engage in a sexual relationship.