half to two
This was the use of a substance generally called barkstone , which they found to be of great help to them in the capture of that animal . The barkstone or castoreum , as it is commercially known , was obtained principally from the beaver himself . The basis of it was an acrid secretion with a musky odor of great power , found in two glands just under the root of the beaver 's tail . Each gland was from one and one half to two inches in length . The boys cut out these glands and squeezed the contents into an empty tin can . This at first was of a yellowish-red color , but after a while , when it dried , it became a light brown . This substance formed the main ingredient of barkstone , and in their medicine chest they found a part of the remainder .