We know that Leonardo had made a series of studies of the shells of the seashore, though ordinarily it was presumed that his studies had been directed rather to their artistic beauty than to scientific knowledge with regard to them. Apparently his very familiarity with them, however, led him to lay the foundation stone of the science of palaeontology. There are {24} sketches of a number of the spiral shells to be found in his notebooks. These are all charming in their pretty curves, and they caught his artistic eye. Nature never makes anything merely useful. This strong outwardly rude cover of shell for the amorphous ugly shellfish--that is, ugly according to most human standards--is very pretty in its forms and its color. The fine use that Leonardo made of his study in seashells was pointed out by someone who studied some of the spiral staircases for the corners of palaces in Northern Italy which Leonardo is said to have planned. These were only private stairways leading usually from the ladies' apartments to the gardens of the castles and were probably designed to be useful as fire escapes. They projected sometimes from the angles of the building. We know what hideous things fire escapes can be. These were very pretty and effectively decorative. They were planned in imitation of the spirals of some of the whorl seashells that Leonardo had been studying. Everywhere we find that mixture of the devotion to the useful and the practical as well as the aesthetic, to the scientific as well as the artistic. He made a series of dissections. These dissections were made at a time when, if we would believe certain of our modern historians of science in its relation to religion, the Church had absolutely forbidden dissection. Such declarations are all the more incomprehensible because not only did all the anatomists and surgeons of this century do dissection quite freely, and the greatest dissections were done in Rome by the Papal Physicians in the Papal Medical School, but every artist of the time studied anatomy for art purposes through dissections. We have dissections from Raphael and from Michelangelo and from many others as well as from Leonardo da Vinci.