The farmer here had shot a small beaver and I questioned him as to what beavers eat. The answer was the bark of birch, pine and rowan but, for preference, aspen bark. If the beaver can get a plentiful supply of this, its castor gland grows bigger. This fact is confirmed by Assessor Rothman, who had earlier expressed the opinion that the substance from which beaver castor is produced is the middle layer of the bark of the aspen tree and that the latter has the same smell though it is not so strong. A decoction of that bark ought, therefore, to have the same effect, if a large enough dose is taken.