Eugenics Laboratory Lectures number 3: Elderton, Ethel M. 1909. The Relative Strength of Nurture and Nature (London: Dulau and Co.). 40 pp. Includes two Appendices: Appendix A, ‘Home Conditions and Eyesight’, by Karl Pearson (noted as reprinted from British Medical Journal), pp. 34–39, and Appendix B, ‘Cleanliness and Vision’, signed Karl Pearson, pp. 439–40. The preface notes that this Lecture summarizes three Memoirs (V, VII, and VIII). Second edition is 1915, noted as ‘much enlarged edition’ of two parts (60 pp. in total): Part I. The Relative Strength of Nurture and Nature. Second edition, revised. By E. M. Elderton; and Part II. Some Recent Misinterpretations of the Problem of Nurture and Nature. First issue. By Karl Pearson.