That they have two eyes is the common opinion; but if they have two eyes, we may grant them to have no less than four, that is, two in the larger extensions above, and two in the shorter and lesser horns below; and this number may be allowed in these inferior and exsanguineous animals,5 since we may observe the articulate and latticed eyes in flies, and nine in some spiders: and in the great phalangium spider of America, we plainly number eight.

But in sanguineous animals, quadrupeds, bipeds, or man, no such number can be regularly verified, or multiplicity of eyes confirmed; and therefore what hath been under this

5 and this number may be allowed, &c.] This remark, in the 6th edition, supplies the place of the following:-the succeeding paragraph which also occurs in all the earlier editions, was omitted in the 6th"which will be monstrous and beyond the affirmation of any.

"Now the reason why we name these black strings eyes, is because we know not what to call them else, and understand not the proper use of that part, which indeed is very obscure, and not delivered by any, but may probably be said to assist the protrusion and retraction of their horns, which being a weak and hollow body, require some inward establishment to confirm the length of their advancement, which we observe they cannot extend without the concurrence hereof; for if with your finger you apprehend the top of the horn, and draw out this black and membranous emission, the horn will be excluded no more; but if you clip off the extremity, or only singe the top thereof with aqua fortis, or other corrosive water, leaving a considerable part behind, they will nevertheless exclude the horns, and therefore explorate their way as before; and indeed the exact sense of these extremities is very remarkable, for if you dip a pen in aqua fortis, oil of vitriol, or turpentine, and present it towards these points, they will at a reasonable distance decline the acrimony thereof, retiring or distorting them to avoid it; and this they will nimbly perform, if objected to the extremes, but slowly or not at all if approached unto their roots."

The various readings given in this and the preceding note, prove that the earlier opinions of Sir Thomas were more in conformity with the sagacious assertion of the great naturalist of antiquity,-and, I may add, with the conclusions which the investigation of Sir Everard Home, and other distinguished naturalists, have recently led them to form. The paper by Mr. Brayley, referred to in note 3, p. 318, will be found to contain a detailed and very interesting account of those investigations. Sir E. Home has pointed out the mistake of Swammerdam, whose microscopic examinations led him to consider the black rete mucosum, at the point of the horn, as nigrum pigmentum, and a pellucid part which he found there, as the cornea. Sir Thomas was probably misled by similar investigations, or he might have seen Swammerdam's work, which appeared in Dutch some years before the sixth edition of the Vulgar Errors.

kind delivered, concerning the plurality, paucity, or anomalous situation of eyes, is either monstrous, fabulous, or under things never seen, includes good sense or meaning. And so may we receive the figment of Argus, who was an hieroglyphick of heaven, in those centuries of eyes expressing the stars, and their alternate wakings, the vicissitude of day and night. Which strictly taken cannot be admitted, for the subject of sleep is not the eye, but the common sense, which once asleep, all eyes must be at rest. And therefore what is delivered as an emblem of vigilancy, that the hare and lion do sleep with one eye open, doth not evince they are any more awake than if they were both closed. For the open eye beholds in sleep no more than that which is closed, and no more one eye in them than two in other animals that sleep with both open, as some by disease, and others naturally, which have no eyelids at all.

As for Polyphemus, although the story be fabulous, the monstrosity is not impossible. For the act of vision may be performed with one eye, and in the deception and fallacy of sight, hath this advantage of two, that it beholds not objects double, or sees two things for one. For this doth happen when the axis of the visive cones, diffused from the object, fall not upon the same plane, but that which is conveyed into one eye, is more depressed or elevated than that which enters the other. So if, beholding a candle, we protrude either upward or downward the pupil of one eye, the object will appear double; but if we shut the other eye, and behold it with one, it will then appear but single, and if we adduce the eye unto either corner, the object will not duplicate, for in that position the axis of the cones remains in the same plane, as is demonstrated in the optics and delivered by Galen, in his tenth, De usu partium.

Relations also there are of men that could make themselves invisible, which belongs not to this discourse, but may

• it beholds not objects double.] In connection with this very curious question of single vision with two eyes, Dr. Wollaston read a short paper to the R. S. in February, 1824, on semi-decusation of the optic nerves. A subject to which he had been led by a singular species of blindness which had affected him—in which he had suffered a temporary loss of sight on the left side only of both eyes. See Quarterly Journal, vol. xvii. p. 227.

serve as notable expressions of wise and prudent men, who so contrive their affairs, that although their actions be manifest, their designs are not discoverable. In this acception there is nothing left of doubt, and Giges ring remaineth still amongst us, for vulgar eyes behold no more of wise men than doth the sun; they may discover their exterior and outward ways, but their interior and inward pieces he only sees, that sees into their beings.

CHAPTER XXI.

That the Chameleon lives only upon air.

CONCERNING the Chameleon,7 there generally passeth an opinion that it liveth only upon air, and is sustained by no other aliment. Thus much is in plain terms affirmed by Solinus, Pliny, and others, and by this periphrasis is the same described by Ovid.8 All which notwithstanding, upon enquiry I find the assertion mainly controvertible, and very much to fail in the three inducements of belief.

And first for its verity, although asserted by some, and traditionally delivered by others, yet is it very questionable.

7 Concerning the Chameleon, &c.] It is singular that Sir Thomas has not mentioned the vulgar opinion that this reptile undergoes frequent changes of colour according to that of the bodies near it. He has assigned some probable grounds for its being supposed to feed on air, viz. its powers of abstinence and its faculty of self-inflation. It lives on insects, which it catches by means of its long gluey tongue, and crushes between its jaws. It has been ascertained by careful experiment that the chameleon can live without eating for four months. It can inflate, not only its lungs but its whole body, including even the feet and tail. The frequent variations of colour observed in the chameleon are by no means determined by those of surrounding objects. They depend on the volition of the animal, or the state of its feelings, on its good or bad health, and are, besides, subordinate to climate, age, and sex. A. Ross so resolutely withstands the Doctor's arguments against the common opinion, as even to assert that flies are eaten by the chameleon, "rather out of wantonness or for physic." He adverts indeed to the fact, only as giving a reason for the animal being provided with digestive organs; but says that the slime on the tongue is not intended for catching the flies, but for destroying serpents, on whose approach the chameleon drops some of the slime on the head of the serpent, which presently dies. Ovid.] See Metam. 1. xv. fab. 4. 1. 411. VOL. I.

Y

For beside Ælian, who is seldom defective in these accounts, Aristotle, distinctly treating hereof, hath made no mention of this remarkably propriety, which either suspecting its verity, or presuming its falsity, he surely omitted; for that he remained ignorant of this account, it is not easily conceivable, it being the common opinion, and generally received by all men. Some have positively denied it, as Augustinus, Niphus, Stobæus, Dalechampius, Fortunius Licetus, with many more; others have experimentally refuted it, as namely Johannes Landius, who in the relation of Scaliger, observed a chameleon to lick up a fly from his breast. But Bellonius* hath been more satisfactorily experimental, not only affirming they feed on flies, caterpillars, beetles, and other insects, but upon exenteration he found these animals in their bellies; whereby we might also add the experimental decisions of the worthy Peireschius and learned Emanuel Tizzanius, in that chameleon which had been often observed to drink water, and delight to feed on meal-worms. And although we have not had the advantage of our own observation, yet we have received the like confirmation from many ocular spectators.

2. As touching the verisimility or probable truth of this relation, several reasons there are which seem to overthrow it. For first, there are found in this animal, the guts, the stomach, and other parts official unto nutrition ; which, were its aliment the empty reception of air, their provisions had been superfluous. Now the wisdom of nature abhorring superfluities, and effecting nothing in vain, unto the intention of these operations, respectively contriveth the organs, and therefore where we find such instruments, we may with strictness expect their actions, and where we discover them not, we may with safety conclude the non-intention of their operations. So when we perceive that bats have teats, it is not unreasonable to infer they suckle their younglings with milk; but whereas no other flying animal hath these parts, we cannot from them expect a viviparous exclusion. but either a generation of eggs, or some vermiparous sepa ration, whose navel is within itself at first, and its nutrition after not connexedly depending of its original.

*Comment in Ocell. Lucan.

Again, nature is so far from leaving any one part without its proper action, that she ofttimes imposeth two or three labours upon one, so the pizzle in animals is both official unto urine and to generation; but the first and primary use is generation, for some creatures enjoy that part which urine not. So the nostrils are useful both for respiration and smelling; but the principal use is smelling, for many have nostrils which have no lungs, as fishes, but none have lungs or respiration, which have not some show or some analogy of nostrils. Thus we perceive the providence of nature, that is, the wisdom of God, which disposeth of no part in vain, and some parts unto two or three uses, will not provide any without the execution of its proper office, nor where there is no digestion to be made, make any parts inservient to that intention.

Beside the remarkable teeth, the tongue of this animal is a second argument to overthrow this airy nutrication; and that not only in its proper nature, but also its peculiar figure. For of this part, properly taken, there are two ends; that is, the formation of the voice and the execution of taste; for the voice, it can have no office in chameleons, for they are mute animals; as, beside fishes, are most other sorts of lizards.

As for their taste, if their nutriment be air, neither can it be an instrument thereof; for the body of that element is ingustible, void of all sapidity, and, without any action of the tongue, is by the rough artery or weazand conducted into the lungs. And therefore Pliny much forgets the strictness of his assertion, when he alloweth excrements unto that animal, that feedeth only upon air; which notwithstanding, with the urine of an ass, he commends as a magical medicine upon our enemies.

The figure of the tongue seems also to overthrow the presumption of this aliment, which, according to exact delineation, is in this animal peculiar, and seemeth contrived for prey. For in so little a creature it is at the least a palm long, and being itself very slow in motion, hath in this part a very great agility; withal its food being flies, and such as suddenly escape, it hath in the tongue a mucous and slimy extremity, whereby upon a sudden emission it inviscates and tangleth those insects. And therefore some have thought