1. Proc. R.S., B, 1924, vol. 96, p. 349; 1925, vol. 98, p. 188; NATURE, 1925, vol. 115, p. 82.
2. N. Giorn. Bot. Ital., 1916, vol. 23, p. 51; résumé in Arch. Ital. de Biol., 1916, vol. 65, p. 219.
3. NATURE, 1925, vol. 116, p. 376; Proc. R.S., B, 1925, vol. 98, p. 290.
4. Bot. Gaz., 1896, vol. 22, pp. 296, 297.
5. Beitr. z. allg. Bot., 1923, vol. 2, pp. 260–262; Zeitschr. f. Bot., 1925, vol. 17, p. 260 and p. 261. I am informed that, also in Oxford, the passage of a stimulus across an organic discontinuity in the stem has been demonstrated.