Navicular Disease

This in the horse is a sprain of the strong flexor tendon of the foot, where it pa es over the navicular bone, in the hollow of the fetlock. It is caused by subjecting light young animals to severe work on hard roads. It is recognized by tripping, heat, tenderne , and swelling of the part, and in more advanced cases wasting of the muscles of the leg and undue wear of the toe of the shoe. Treatment consists of rest, hot applications, bandaging, and a soft bed; after the inflammation has subsided the animal should be placed on soft land. cluding determination of the latitude, longitude, and course of the ve el. Previous to 1400 the science hardly existed; although the properties of the magnetic needle were known much earlier, the general introduction of the Mariner's Compa was a slow proce , the early instruments being rude affairs, frequently of little use. The early navigators were therefore obliged to limit their operations mainly to coasting along the shore, or if they ventured out to sea it was at great peril. During the 15th century a number of important important exp lor exploring expeditions were sent out by the Portuguese: Prince Henry, and after him John II., took active measures to collect and improve the available knowledge on this subject. An observatory was established at Sagres, in order to obtain better tables of the sun, and a government committee of navigation was instituted. This may be regarded as the origin of the science of navigation in Europe. The appliances of the navigator at that time were a cro -staff or astrolabe (rude instruments for measuring the sun's altitude), a compa , tables of the sun's declination, tables for correcting the altitude of the pole star, and sometimes a rough chart. Even the log for measuring the ve el's velocity was not invented until 1607. Since then almost every science and art has contributed to the comfort, safety, and convenience of the mariner, and the perils of navigation have almost disappeared.