The story was ridiculed and rejected by no less a philosopher than Roger Bacon in the thirteenth century, and was also discredited by the learned Aristotelian Albertus Magnus at about the same time. No trace of it is to be found in Aristotle or Herodotus or any classical author, nor in the "Physiologus." The legend seems to have originated in the East, for the earliest written statement which we have concerning it is by a certain Father Damien, in the eleventh century, who simply declares: "Birds can be produced by trees, as happens in the island of Thilon in India." We have also a reference to the same marvel in an ancient Oriental book (the "Zohar," the principal book of the Kaballah), as follows: "The Rabbi Abba saw a tree from the fruits of which birds were hatched." The earliest written statements of the legend are, it appears, to the effect that there is a tree which produces fruits from which birds are hatched. The belief in the story seems to have died out at the end of the seventeenth century, when the structure of the barnacle lying within its shell was examined without prejudice, and it was seen to have only the most remote resemblance to a bird. The plumose legs or "cirrhi" of the barnacle (Fig. 10) have a superficial resemblance to a young feather or possibly to the jointed toes of a young bird, and there the possibilities of comparison end. The notion that a particular kind of black goose (a "brent"), which occurs on the marshy coast of Britain in great numbers, is _the_ goose, _the_ bird, produced by the barnacle was favoured by the fact that this goose does not breed in Britain, and yet suddenly appears in large flocks, in districts where barnacles attached to rotting timber are often drifted on to the shore. It was accordingly assumed by learned monks--_who already knew the traveller's tale_, that in distant lands birds are produced by the transformation of barnacles--that this goose is the actual bird which is bred from the barnacles, and it was accordingly called "the barnacle goose." I think that this identification was due to the exercise of a little authority on the part of the clergy in both France and Britain, who were thus enabled to claim the abundant "barnacle goose" as a fish in its nature and origin rather than a fowl, and so to use it as food on the fast-days of the Church. Pope Innocent III (to whom the matter was referred) considered it necessary in 1215 to prohibit the eating of "barnacle geese" in Lent, since although he admitted that they are not generated in the ordinary way, he yet maintained (very reasonably) that they live and feed like ducks, and cannot be regarded as differing in nature from other birds.