Appendix I, p. 351-353: Experiments with B. typhosus re adaptation, by F. B. Bowman. Appendix II, p. 354-361: Sir E. Lankester rebukes rudeness; a correspondence [with the author] in the pages of the British medical journal. Title vignette. "The Croonian lectures upon adaptation and disease, delivered in June 1917 ... from the first part of this volume."--Pref.