In order to maintain the elastic tissues of the foot in their proper activity, regular and _abundant exercise_, with protection against drying out of the hoof, are absolutely necessary, because the movements of the different structures within the foot and the changes of form that occur at each step are indispensable in preserving the health of the hoof. Long-continued rest in the stable, drying out of the hoof, and shoeing decrease or alter the physiological movements of the foot, and these lead under certain conditions to foot diseases, with which the majority of horse owners are entirely unacquainted. As an outward, visible indication of the mobility of the quarters upon the shoe we may point to the conspicuous, brightly polished, and often sunken spots, or grooves, upon the ends of the branches. They are produced partly by an in-and-out motion of the walls at the quarters, and partly by a forward and backward gliding of the quarters upon the shoe. _The benefits of these physiological movements_ within the hoof are manifold: 1. Through them shock is dispersed and the body protected from the evil consequences of concussion or shock. 2. These movements increase the elasticity of the entire limb, and in this way contribute much to a light and elegant gait. 3. They maintain a lively circulation of blood in the vessels of the pododerm, and this insures a rapid growth of horn. Since it is a generally accepted fact that shoeing interferes with the physiological movements of the hoof, alters them, indeed, almost suppresses them, and that all these movements are spontaneous and natural only in sound _unshod_ hoofs, we are justified in regarding shoeing as a _necessary evil_. However, it is indispensable if we wish to render horses serviceable upon hard artificial roads. If, in shoeing, consideration be given to the structure and functions of the hoof, and particularly to the hoof-surface of the shoe, the ends of the branches being provided with a smooth, level bearing-surface, which allows free play to the elastic horn capsule, in so far as this is not hindered by the nails we need have no fear of subsequent disease of the hoofs, provided the horse is used with reason and receives proper care. PART II. CHAPTER III. SHOEING HEALTHY HOOFS. A. Examination of a Horse Preliminary to Shoeing. An examination should be made while the animal is =at rest=, and afterwards while =in motion=. The object of the examination is to gain accurate knowledge of the direction and movements of the limbs, of the form and character of the feet and hoofs, of the manner in which the foot reaches and leaves the ground, of the form, length, position, and wear of the shoe, and distribution of the nail-holes, in order that at the next and subsequent shoeings all ascertained peculiarities of hoof-form may be kept in mind and all discovered faults of shoeing corrected.