Fifty years of Darwinism.--The personality of Charles Darwin.--The Darwin centenary at Oxford.--Charles Darwin and the University of Cambridge.--The value of colour in the struggle for life.--Mimicry in the butterflies of North America.--Letters from Charles Darwin to Roland Trimen.--Appendix A. Charles Darwin and the hypothesis of multiple origins.--Appendix B. Darwin and evolution by mutation.--Appendix C. Further proof that scientific work was necessary for Darwin.--Appendix D. De Vries's 'fluctuations' hereditary according to De Vries, non-transmissible according to Bateson and Punnett.