Leonardo proposed after making a large number of dissections to write a text-book of anatomy. Ordinarily it might seem that such a text-book from an artist's hands would be eminently superficial and not at all likely to further the science of anatomy, though it might be helpful for students of art, especially in their dissection work. During the past twenty years, however, a series of Leonardo's sketches made from his dissections have been republished from a number of {25} collections of the originals in important libraries in Europe. The collection at Windsor Castle in England is particularly valuable and the sketches are very complete. Anyone who looks over these republications will realize at once that had Leonardo written his text-book of anatomy and illustrated it with his own drawings, it would have been an epoch-making landmark in the history of anatomy and of medicine. It was not until a quarter of a century after the artist's death that Vesalius, but five years old when Leonardo died, published his great anatomical text-book. At the time Vesalius was only twenty-seven years of age, but his work revolutionized anatomy and he is rightly greeted as the father of modern anatomy. Had Vesalius had the opportunity to consult Leonardo's work, his own would have been greatly facilitated. It was not merely anatomy for art purposes but for all purposes, scientific as well as artistic, that Leonardo with characteristic thoroughness had studied. There are studies of his in zoology, made evidently for the sake of his work in sculpture, that represent important additions to this scientific department. The same thing is true with regard to botany. Flowers caught his artistic eye, but they appealed quite as much to the scientific sense and so we find sketches of many varieties of them that are very interesting but also very startling from a scientific standpoint because they show a knowledge of the parts of the flowers in detail not usually supposed to exist at that time. One is not surprised to hear that he did distinguished work in mathematics. Somehow the exact scientific bent of his mind and its literalness in all matters pertaining to science would lead us to expect that. There probably never has been a mind so thoroughly rounded out as his. Aristotle had greater scientific precision and wider knowledge, but lacked something at least of Leonardo's power to execute his artistic ideas, or we would surely have some great art from him or traditions of it. It is even not startling, with this knowledge of the scientific side of Leonardo's mind, to find that he advanced a theory of evolution. That generalization far from being new, as is often imagined, has appealed to many great investigating minds down the centuries, according to the title of a modern {26} scientist's history of the theory all the way "From the Greeks to Darwin."