I remember one incident which bears upon this part....

“ I remember one incident which bears upon this part of the treatise. The gentleman who gave it to me had asked to see my tobacco-pipe; he examined it carefully, and when he came to the little protuberance at the bottom of the bowl he seemed much delighted, and exclaimed that it must be rudimentary. I asked him what he meant."Sir," he answered, "this organ is identical with the rim at the bottom of a cup; it is but another form of the same function. Its purposes must have been to keep the heat of the pipe from marking the table upon which it rested. You would find, if you were to look up the history of tobacco-pipes, that in early specimens this protuberance was of a different shape to what it is now. It will have been broad at the bottom, and flat, so that while the pipe was being smoked the bowl might rest upon the table without marking it. Use and disuse must have come into play and reduced the function its present rudimentary condition. I should not be surprised, sir," he continued, "if, in the course of time, it were to become modified still farther, and to assume the form of an ornamental leaf or scroll, or even a butterfly, while in some cases, it will become extinct. ”

Samuel Butler

From : Erewhon