Attracted by the beauty and diversity of orchids, Darwin began a study of the anatomy and reproduction of these complicated plants. Armed with tin cans and biscuit boxes, he tramped the fields securing specimens. It was back to basics - observing and experimenting. However, the treadmill of letter-writing continued. Orchids was his first theoretical work after Origin and the first to provide supporting evidence to it. It was the only Darwin publication not bound in green. This is the second edition revised.
Charles Darwin, The Various Contrivances by which Orchids are Fertilised by Insects. 2nd ed. rev. London: John Murray, 1877. Leith Storage F3D
The Variation of Animals and Plants Under Domestication contained Darwin's 'pangenesis', his provisional hypothesis on the inheritance of acquired characteristics, which he hoped would plug the gap left in the Origin of Species. It was a complicated theory that was deeply flawed. Sales proved poor, with only some 5,000 copies sold in Darwin’s life-time. Indeed, he told Hooker: 'Skip the whole of vol. I, except the last chapt (& that need only be skimmed) & skip largely in 2nd vol., then you will say it is a very good book.'
____, The Variation of Animals and Plants Under Domestication. Vol. I. London: John Murray, 1868. Science EO9 D
The Expression of the Emotions (1872) was written to refute arguments that facial muscles were possessed uniquely by man. A catalyst to this work was Oscar Rejlander's photograph of the screaming baby; one question Darwin asked was: 'What did the little Huxley’s eyebrows do?' While important as extension of his account of evolution, Expression of the Emotions is also the first book on ethology (animal behavior) and thereby a direct contribution to psychology. It was the only work by Darwin illustrated with photographs.
____, The Expression of the Emotions in Man and Animals. London: John Murray, 1873. Kind permission of Canterbury Medical Library and the Cotter Medical History Trust
After planting seeds received from Asa Gray, Darwin 'was so much fascinated and perplexed by the revolving movements of the tendrils and stems, which movements are really very simple, though appearing at first sight very complex, that I procured various other kinds of climbing plants, and studied the whole subject...' (Autobiography). Originally a paper for the Linnean Society, Movement and Habits was enlarged and published as a second edition in 1875. This is the later, 1905 edition.
____, The Movements and Habits of Climbing Plants. London: John Murray, 1905. Leith Storage F3D