Every unexpected occurrence was pressed into service. Witness the following anecdote: "One day my horse was much frightened at a drilling machine, covered by a tarpaulin and lying on an open field. He raised his head so high that his neck became almost perpendicular; and this he did from habit, for the machine lay on a slope below, and could not have been seen with more distinctness through the raising of the head; nor if any sound had proceeded from it could the sound have been more distinctly heard. His eyes and ears were directed intently forwards; and I could feel through the saddle the palpitations of his heart. With red, dilated nostrils, he snorted violently, and whirling round, would have dashed off at full speed had I not prevented him." We see, too, in this book the results of Darwin's extensive reading. The novelists are laid considerably under contribution, their power of describing expressive signs of emotion being particularly appreciated. Dickens, Walter Scott, Mrs. Oliphant, and Mrs. Gaskell are among the novelists quoted; while the author of Job, Homer, Virgil, Seneca, Shakespeare, Lessing, Sir Joshua Reynolds, and many other deceased writers, illustrate the subject. The living authorities--scientific men, travellers, doctors--referred to for facts are exceedingly numerous, including Sir James Paget, Professor Huxley, Mr. Herbert Spencer, Sir J. Crichton Browne, Sir Samuel Baker, Sir Joseph Lister, Professors Cope and Asa Gray, and many others. One of the most interesting chapters in the book is that dealing with blushing. It is shown to depend on self-attention, excited almost exclusively by the opinion of others. "Every one feels blame more acutely than praise. Now, whenever we know, or suppose, that others are depreciating our personal appearance, our attention is strongly drawn towards ourselves, more especially to our faces." This excites the nerve centres receiving sensory nerve for the face, and in turn relaxes the blood capillaries, and fills them with blood. "We can understand why the young are much more affected than the old, and women more than men, and why the opposite sexes especially excite each others' blushes. It becomes obvious why personal remarks should be particularly liable to cause blushing, and why the most powerful of all the causes is shyness; for shyness relates to the presence and opinion of others, and the shy are always more or less self-conscious."