Lankester served as a leader for the Church Missionary Society examining board in addition to his role as a secretary. He retired in 1926 after serving there for 30 years During this period, he served as Secretary of the Auxiliary Committee on Medical Missions, Society Physician, Home Secretary and General Secretary. He published numerous papers as the Honorary Secretary of Committee. In Occasional Paper 1, Lankester wrote an Appeal to the Medical Mission Auxiliary Fund Committee. Lankester worked as a researcher. He enjoyed reading and studying why people became ill. He read every book of medicine that was available at the time.
