Beaver skins lured the hunter and trapper over all American wilds. These skins were one of the earliest mediums of exchange among the settlers of North America. For two hundred years they were one of the most important exports, and for a longer time they were also the chief commodity of trade on the frontier. A beaver skin was not only the standard by which other skins were measured in value, but also the standard of value by which guns, sugar, cattle, hatchets, and clothing were measured. Though freely used by the early settlers for clothing, they were especially valuable as raw material for the manufacture of hats, and for this purpose were largely exported. From this animal were prepared many remedies which in former times were believed to have high medicinal value. Castoreum was the most popular of these, and from it was compounded the great cure-all. The skin of the beaver was thought to be an excellent preventive of colic and consumption; the fat of the beaver efficient in apoplexy and epilepsy, to stop spasms, and for various afflictions of the nerves. Powdered beaver teeth were often given in soup for the prevention of many diseases. The castoreum of the beaver was considered a most efficient remedy for earache, deafness, headache, and gout, for the restoring of the memory and the cure of insanity. Next in importance to its skin, the beaver was valued for the castoreum it yielded. The old hunters, trappers, and first settlers forecast with confidence the weather from the actions of the beaver. This animal was credited with being weather-wise to a high degree. From his actions the nature of the oncoming winter was predicted, and plans to meet it were made accordingly. Faith in the beaver's actions and activities as a basis for weather-forecasting was almost absolute. If the beaver began work early, the winter was to begin early. If the beaver laid up a large harvest, covered the house deeply with mud, and raised the water-level of the pond, the winter was, of course, to be a long and severe one.