In comparing ancient or mediæval zoology with modern, we are conscious of a difference of aim and treatment. The study of the present day is largely devoted to the life-history of the creatures themselves, their structure, and so forth; while in former times the writer strove ordinarily after an entirely different aim, thinking much less of these external facts, but dwelling upon the value of the animal to mankind in one of two directions. While we occasionally in books of travels have the more modern and descriptive treatment, the main bulk of the writings on animals in mediæval days had ordinarily one of two objects: the healing of the body, or the saving of the soul. Hence the medical writers sought anxiously for “the vertues” that indicated their value to suffering humanity, and the theologians sought with equal zeal to implant a moral, and if the facts in this latter case did not lend themselves very happily to this treatment so much the worse for the facts. As an illustration of this moral-pointing treatment we find in one of these old writers that “polypus is a fish with many feet, and a rounde head neare unto them: it is a great enemy to the lobster, and they can often change their colour, and by that project devoure other fishes. Their use and custom is to be lurking closely by the sides and roots of rocks, changing themselves into the colour of the same thing unto which they cleave: insomuch that they seem as a part of the rock; whither when the foolish fish swim they fall into danger, for whilst they dread nothing these polypodes suddenly prey upon them and devoure them. And indeede this is the constancie and unfeared treacherie which is often found in many men, who will be anything for their own ends. And nothing without them: sparing none for their own purposes, nor loving any but to effect them. Their heads, indeed, may well be neare their feet; for they prize the trash we trample on farre above the joyes of heaven; else they would never work their fond purposes by deceitfull meanes and damage others to help themselves.” Another illustration of the same kind states that “although the mole be blinde all her lifetime, yet she beginneth to open her eyes in dying: whiche is a prettie embleme. This serveth to decypher the state of a worldly man, who neither seeth heaven nor thinketh of hell in his lifetime, untill he be dying: and then beginning to feel that which before he either not believed or not regarded, he looketh up and seeth. For even against his will he is then compelled to open his eyes and acknowledge his sinnes, although before he could not see them.” We have taken these two passages from the “Speculum Mundi, or a Glasse representing the Face of the World, whereunto is added a Discourse of the Creation, together with a Consideration of such things as are pertinent to each dayes Worke.” It was written by one John Swan, and the copy before us as we write bears date 1635.[1] It is a good