many-chambered ‘test,’ that resembles in form the chambered shell of an orthoceratite—the conical mouth of each chamber projecting into the cavity of the next—while forming the walls of its chambers of ordinary sand grains rather loosely held together, shapes the conical mouth of the successive chambers by firmly cementing together grains of ferruginous quartz, which it must have picked out from the general mass.” “To give these actions,” continues Dr. Carpenter, “the vague designation of ‘instinctive’ does not in the least help us to account for them, since what we want is to discover the _mechanism_ by which they are worked out; and it is most difficult to conceive how so artificial a selection can be made by a creature so simple” (Mental Physiology, 4th ed. pp. 41–43) This is what protoplasm can do when it has the talisman of faith—of faith which worketh all wonders, either in the heavens above, or in the earth beneath, or in the waters under the earth. Truly if a man have faith, even as a grain of mustard seed, though he may not be able to remove mountains, he will at any rate be able to do what is no less difficult—make a mustard plant. Yet this is but a barren kind of comfort, for we have not, and in the nature of things cannot have, sufficient faith in the unfamiliar, inasmuch as the very essence of faith involves the notion of familiarity, which can grow but slowly, from experience to confidence, and can make no sudden leap at any time. Such faith cannot be founded upon reason,—that is to say, upon a recognised perception on the part of the person holding it that he is holding it, and of the reasons for his doing so—or it will shift as other reasons come to disturb it. A house built upon reason is a house built upon the sand. It must be built upon the current cant and practice of one’s peers, for this is the rock which, though not immovable, is still most hard to move.