Right and Left

IT is claimed by mathematicians that their ancient science underlies all others. No doubt they are correct; for theirs is, essentially, the science of space and of time, without reference to which we can neither think nor act upon this earth. It may be doubted how far a practical acquaintance with the ways and means of any other than the simplest mathematics is required in the every-day life of the ordinary business or professional man; but it is certain that the three characteristic signs, o, +, —, (zero, plus, minus), may be taken to represent the three successive stages of human thought upon most questions, great or small, in the other, even the least kindred, branches of knowledge.

At first we know nothing. Zero is the full extent of our information.

Then follows an accumulation of facts and development of ideas, which sooner or later crystallize into theories, broad and sweeping, and so eminently satisfactory, that no further inquiry seems necessary ; and this stage, which appears to be complete or to be susceptible only of addition, is fitly represented by the sign plus.

The third stage may be long deferred, but is sure to come. It is when exceptions are found to the supposed universal rules; when new facts are discovered, and old ones prove capable of a different interpretation, so that each year takes something from the accepted theories, which finally are seen to be either wholly false, or true only so far as is compatible with some more comprehensive law now brought to light.

Chaos became a broad, unbroken ocean, but afterward the dry land appeared. Too little is followed by too much, and the happy mean comes later.

Vacuity is succeeded by the ideal, which in turn must give place to the real.

Fancy fills a great void in the mind, but must yield, in part at least, to fact.

Ignorance is the parent of conceit, and this, by grace of God, may give birth to humility, — to the humble acknowledgment of the truth.

Paganism, and the denial of a true God, gave way to Romanism ; and this is now everywhere breaking down before the slow but sure advance of liberal Christianity.

Let us now inquire how far this succession of states may be detected in the history of a single question in science.

There has doubtless been a time when men saw not, or if they saw, appreciated not, that dual composition of the most beautiful objects of nature, — the human face and the whole human form, certain regular crystals and many leaves,—which has since been so universally recognized, and which, under the name of symmetrical beauty, has been a standing law in art of every kind; so that the highest results of painting and of architecture — the ideal face and the Greek temple and Gothic church — are or are intended to be composed of two equal and identical halves upon opposite sides of a mesial plane.

But although this idea of perfect symmetry has been thus adopted as a rule in art, admitted in theory and followed in practice as a first and indispensable step toward pre-eminence, it by no means follows that it is true to nature; and it behooves us, whether as artists or as naturalists, to examine carefully all the facts, and see whether they justify a continuance of our belief in the law of perfect symmetry, or of absolute identity between two halves of anything.

If not, then we may be ready to enter upon the third stage of the subject, and are bound to examine each statement, whether new or old, in the light of a possible reversal of previous opinions.

Having done this with all the information at my command, conclusions have been reached which may be briefly expressed by the following six proposition : —

I. That many of the most beautiful and useful objects in nature and art are symmetrical; that is, composed of two similar halves separated by a common mesial plane.

II. That these two similar halves, when carefully examined, are never found to be identical either in form or function.

III. That many objects in nature are manifestly composed of two unequal halves.

IV. That in all cases of marked departure from symmetry in the adult, a less deviation exists at an earlier period of life.

V. That deviations from symmetry ought eventually to be divided into three classes, which may be called Abnormal, Teleological, and Normal.

VI. That there are principles, natural, human, and Divine, which require that the more perfect and highly organized forms should consist of two similar halves separated by a mesial plane, but which at the same time forbid that these two similar halves should ever be absolutely identical.

If it is objected that the halves of anything cannot be unequaland that some other term — as part or moiety or portion — ought to be used, I ask the critic to suspend judgment until the end of this article ; by which time he may be convinced that, although in the dictionary, in many scientific works, and in nearly all popular ones, halves are defined as equal and identical portions, yet in all probability neither equality nor identity can exist in nature.

I.

Our first proposition is, that many of the most beautiful and useful objects in nature and in art are symmetrical, that is, composed of two similar halves separated by a mesial plane.

As this is the generally accepted doctrine upon the subject, and the very one we wish to qualify, we are not called upon to offer any facts in its support; but as the glory of a victory is great in proportion to the real or apparent strength of the enemy, it is well to state briefly the grounds upon which this common belief is based.

A glance in the mirror offers the most accessible series of facts ; there is a right and a left eye, a right and a left nostril, a right and a left ear, the members of each pair being evidently similar ; the two corners of the mouth, the two temples, the two cheeks, and the two sides of the forehead closely resemble each other in shape and in position.

It will be noticed that there are two groups of features ; the nose and mouth and chin and forehead are all upon the middle line, and their right and left halves are to be compared together; they are called single or median organs, and are symmetrical in themselves: but the eyes, the nostrils, the ears, the cheeks, are in pairs, one on each side of the middle line ; they are thus symmetrical with each other, but not in themselves ; that is, the outer half of the right eye corresponds, not to the inner half of the same eye, but to the outer half of the left eye ; and so with the inner halves of the two eyes, so with the inner and outer halves of each nostril. And the same is true of all organs in the body : some being median, single, and symmetrical in themselves ; others, lateral and in pairs, so as to be symmetrical, not in themselves, but with each other.

We have two hands and two feet, two arms and two legs, and the entire right side of the body is the reversed repetition of the left. There is a right and a left lung too, a right and a left kidney, right and left ribs, muscles, nerves, and blood-vessels, which certainly correspond quite closely with each other.

The same is true concerning our common animals, the birds, the reptiles, the fish, and the insects. The symmetrical form of common leaves is so obvious that no one hesitates to say that they consist of two equal halves joined by a midrib. Seeds, like eggs, are often round or oval, and are then regarded as equal upon the two sides; and no one who admits the regularity of crystals and the identity of any two specimens, is likely to deny the still more absolute identity which is supposed to exist between their two halves.

And so we might enumerate all the symmetrically beautiful objects in nature. Many cases are known of inflammation attacking at the same time and in the same way the two elbows or the two knees or the two sides of the pelvis. Occasionally, too, a wound or burn upon one hand or arm or leg will produce pain upon the other, in what is said to be the very same spot; but, as will be seen further on, “to seem is not always to be.” And we ought to exact the most rigid tests from those who claim absolute identity between similar parts on the two sides of the body.

What was so prominent in nature could not fail to be imitated in art; and the portraits, the temples, and the columns of all ages attest the faithfulness of genius to what was thought to be the true ideal of beauty.

The same necessity for symmetry which we observe in birds and in most fishes exists in all bodies which are to be supported by a fluid medium, as the air and the water; and the impression made by a long life spent upon a vessel has sometimes led to an absurd retention of the symmetrical arrangement there required, where no such call for it existed. An old sea-captain, having retired to private life upon the shore, built himself a house of which the door was exactly in the middle, with an equal number of windows upon each side ; the same extent of ground to the right and the left, and the same trees and bushes and flowers in the ground ; but when he found it necessary to have a well, and the land would not admit of placing it in the rear, he consented to its being dug upon one side of the house, only upon the condition that a curb and well-sweep and bucket should be placed upon the other, in order that to appearance, at least, his dwelling should be all trim and “ ship-shape.”

That the ideal standard of the seacaptain and the artist is truly an ideal and not an actual one will be seen in what follows under our second proposition.

II.

That the two similar halves of the so-called symmetrical object, when carefully studied, are never found to be identical in form, position, or function.

This, the reverse of what most people would take to be the signification of the first proposition, is most readily established by prolonging the glance at yourself in the mirror into a careful scrutiny of each feature, and comparing it closely with its fellow of the opposite side.

To begin with the eyes : a very slight examination will show that one is a little more open than the other, or that the upper lid droops at the outer or the inner corner more in one than in the other ; one eyebrow, too, is raised a little higher than the other; neither lids nor brows, it is true, are any part of the eye itself, but they are the chief agents in whatever expression it has: while the not infrequent occurrence of strabismus in its various forms, and even of different colors of the eyes themselves, indicate the possible existence of unsuspected differences between the two organs, which need only more careful looking for to be seen. Everybody knows, too, that the right eye does not see an object just as the left does; and the immense demand for stereoscopic views, though it proves nothing new, tends to confirm the truth of the proposition.

It is not easy to compare the two ears together during life, and their form is so apt to change after death that not much is to be said of them.

But the nose, being the most prominent feature, likewise best exhibits this want of perfect symmetry in its two halves. This usually consists in a greater or less deviation to one side, which is often so great as to give it quite a different outline, as seen from the right or the left side ; either with or without this bending of the nose itself, the bony and cartilaginous partition between the two cavities may vary from the perpendicular so as to approach and even touch the outer wall of one nostril, which is thereby obstructed, either constantly or temporarily, as when there is any inflammation of the mucous membrane. And when no deviation from symmetry is observable in the body of the nose, the nostrils, even in what are called perfect and regular features, differ in size and shape ; and generally the wing of one nostril is elevated a little more than the other.

The mouth participates in the irregularities of the nose, and one angle is always a little more drawn than the other ; the same is to be seen in the cheeks, especially of thin, strong-featured people, so that one entire side of the face appears, and really is, shorter than the other.

It is not easy, either, to see or to describe variations of the chin ; but in the beard, its hairy appendage, there is almost always a difference of the two sides, which persists during life, in spite of all cultivation of the deficient portion.

Deviations from symmetry are extremely common in the bones of the head, and it is doubtful whether any skull is equal upon the two sides. Seldom if ever are the wrinkles of the skin of the forehead equal in number or shape or direction upon the two sides.

All these are illustrations of anatomical or structural deviations from ideal symmetry; but the functional manifestations, though more transient and less often noticed, are none the less significant. Homœopathic practitioners lay great stress upon the predominance of symptoms upon one or the other side of the face or body, and certain it is that even in health a difference may be recognized. There are cases of what is called unilateral sweating of the head; and the blushing of one cheek, with partial or complete paleness of the other, is very common. There is in some cases a very marked alternation of pulse upon the two sides, as if one beat of the heart sent the blood more forcibly to the right, the next to the left side of the body ; this is most easily perceived when one or the other side is inflamed, when, of course, the pulse of that side is exaggerated ; but I have myself felt it in the ordinary pulse at the wrist, and doubt not that the proper examination will demonstrate its universal existence.

There are many other facts in disease which must be due to a difference in either the heart’s action or in the blood-vessels of the organs themselves ; as, for instance, the greater frequency of tubercles in the left lung, and of pneumonia in the right, as if the right were the more vigorous or sthenic half of the body, with the internal organs as well as with the limbs where it is more generally recognized ; and the remarkable tendency of rheumatism to attack, now one, now the other side of the body was doubtless the foundation for the comical answer of a physician when asked concerning a patient treated in common by himself and a fellowpractitioner. “ Well,” said he, “at last accounts my half was doing finely, but Dr. B——’s half was worse than usual.”

Those who wear closely fitting gloves and boots are well aware, though the people who make them seem to ignore the fact, that, as a rule, the right hand and the right foot are larger than the left; and if it be said that this difference was not natural, but is caused by the greater or the different use of one hand and foot, then I ask, What causes all men, with few exceptions, to employ the right hand for striking and the left for holding and supporting, the right foot for kicking and for taking the more vigorous part in propelling the body, while the left supports the body in the one case, and is advanced to be ready to receive its weight in the other? No doubt imitation of others and long - continued habit go far toward perfecting the ready use of the right hand and the right foot, but something else must have originated the habit and the custom. It is found, too, that the left hand is more sensible to changes of temperature than the right, while, as every one knows, it is with the right that we most readily detect variations of shape.

Professor Wyman has found by careful measurements that “in ten human skeletons the bones of the forearms were of equal length in only one,” and even in that a still more minute comparison would probably have shown a difference. He has also compared the concentric rows of papillæ upon the thumbs or the fingers of the two hands, by making an impression of them on paper slightly coated with black, and found in most individuals a very close approach to absolute symmetry, but in others remarkable departures from it, even the entire pattern being changed. Now, slight as this difference seems, it alone is sufficient to establish our point, that an absolute and entire identity has not been found between the two halves of the body.

It is surely something more than habit which causes us to look through a microscope or telescope with one eye rather than with the other, and there have even been perceived by the two eyes two different shades of color from the same flame when viewed through either alone.

It may, too, be something more than mere habit which determines the manner of putting on our clothes : the majority of people putting the right arm first into a coat-sleeve and the right leg into its proper garments. There is, too, — though possibly the garment itself may be responsible for it, — a difference in the way the two legs are raised, the right being elevated and bent in the same plane which it generally occupies, while the left is turned outward and goes through a more extensive series of motions ; but my readers can see all this better than I can describe it.

We are told that the cow and the other ruminating animals chew first with one side and then with the other, so that the direction of the lateral motion of the jaw is reversed at regular intervals ; but in human beings, though less freedom is allowed for a sidewise motion, the muscles work in such a way that the teeth of one side touch before those of the other, and the whole jaw is worked obliquely from right to left or from left to right; this may be partly custom, but the habit is formed unconsciously, and usually persists through life.

A few words upon imperfect symmetry in what are generally considered regular leaves. In the hop-hornbeam (Ostrya Virginica), the casual observer sees no difference between the two halves of each leaf; but if the plant be examined more carefully it will be found that the veins branch off from the midrib, not in pairs, but alternately, so that on one side they begin lower down than upon the other; and now if several leaves be compared together, about half of them will prove to be larger and to have the veins beginning lower down upon the one side, and the rest upon the other side ; and if a pair of leaves upon the stem be contrasted, you will see that in each it is the outer half which is the larger, and the inner which is the smaller. These leaves, then, are not symmetrical in themselves, but with each other, the outer half of one corresponding to the outer half of the other, and the two inner halves in the same way ; and they are therefore right and left, just like the two eyes.

The leaves of elm-trees show this difference still more strikingly, but here it is the inner halves which are the larger and in which the veins commence lower down ; and in many other leaves the difference between the two sides is so great that every one notices them. Our object, however, is to show that the differences may exist even in those where it is not apparent to ordinary observation ; but the facts just given lead naturally to a consideration of our third proposition.

The lack of symmetry which we believe to exist in even the most perfect works of art cannot be described particularly, except by taking up any single picture or edifice, and comparing one side with the other. But when we reflect that so many elements enter into the composition of each work, and that all these, material, color, shape, weight, and position, are so many variables, and that each half must be, by human hands, constructed separately, so that all the variable elements of human action must have a place in our calculation, it is self-evident that, however closely the two sides of a portrait or the two halves of a church or other building may repeat each other, it is absolutely impossible that they should be identical in every respect.

III.

That many objects in nature are manifestly composed of two unequal halves.

Let us begin, as before, with the human body. Marked differences between the two sides of the face are not very rare, but they are generally called deformities,— such as an excessive twist of the nose, an extreme squint or decided strabismus, — but the infinite gradation in all these, and the varied impressions they make upon observers, render it difficult, if not impossible, to draw a distinction between these decided cases and those only to be detected by careful scrutiny. Distortions of the limbs are sometimes alike upon the two sides, but are often different; for instance, out of 703 cases of club-feet, in only 320 were both feet similarly affected; in 182 the right foot was distorted, in 138 the left foot, and in 20 cases one foot was turned outward and the other inward.

Supernumerary teeth occur generally upon only one side of the jaw; in the 152 cases of sexdigitism lately tabulated by me, the 34 individuals who had an extra digit upon two limbs had, except in two cases, two extra thumbs, or two extra little fingers, two great or little toes ; but although the same digit is here repeated upon the two sides, there is always a difference between the two extra ones. The same is true with what are called muscular and nervous and vascular anomalies ; for when these organs are found to vary from the normal condition upon one side of the body only, they of course differ from their fellows of the opposite side ; and even when both vary, they never do so in precisely the same way or to the same extent. But it is among the internal organs of man that the most striking differences exist between the two sides. Even in the brain whose two halves are commonly supposed by anatomists as well as by others to be perfectly equal, the left lobe is generally a little larger than the other; and in some cases this amounts to a real deformity, though no such discrepancy may have been suspected during the life of the individual ; curiously enough, Bichat, a celebrated anatomist, who during life upheld the theory that insanity was due to a disproportion in size of the two halves of the brain, was found himself to be one of the most marked cases of this kind, one lobe of the cerebrum being nearly an inch shorter than the other. It is not often that a man is able after death to correct the very errors he made during his life.

Similar and even more striking differences have been observed in the other parts of the brain. The number, extent, and direction of the convolutions or foldings of the surface of the cerebrum are never the same upon the two hemispheres, and no practical anatomist expects to find the size and the arrangement of the nerves and of their branches precisely alike upon the two sides of the face, or any other part of the body.

Descending into the chest, the heart is found to be more upon the left side, and the right lung to be a little more capacious than the left; but in consequence of the upward pressure of the liver, it is shorter and has only two lobes, while the left lung is longer and has three lobes. The difference in power of the two sides of the heart is well known, but there is, in addition, a difference in the mode of branching of the great arteries as they leave it to go to the head and the arms of the two sides.

In the abdomen, no one thinks of looking for symmetry, for the stomach and pancreas lie on the left, the liver on the right ; while the intestines are coiled up in a very irregular way. Even the two kidneys, as they appear, always differ a little in form and in position, the right being shorter and thicker and lower down than the left. The great artery of the body, the aorta, passes down on the left of the backbone, and the vena-cava ascends upon the right, which produces a difference in the length of all their branches.

Turning now to the lower animals, the same or similar facts meet us wherever we examine with reference to this point. The reason so few facts are on record is that anatomists generally have taken for granted that the two sides were alike, and have made one half do for the whole ; but in view of what is known on this point we have no more right to judge one half from the other than to judge a whole species from a single specimen.

The size of some of the common animals, the hairy coat of most, and the rounded outline of all, render it very difficult to compare the two sides together ; but we cannot fail to note great differences in the smaller and more definitely shaped appendages : as the ears, the horns of cattle and of goats, and the antlers of deer, the spurs of cocks, and the curious appendage hanging from the corner of the lower jaw, in Normandy pigs, which sometimes even exists only on one side.

The narwhal, a kind of whale, is called Monodon, because the male has a long conical tooth projecting from the left side only of the upper jaw, and nearly all of the cetacea present an exaggerated degree of the one-sidedness which we noted in the human nose ; for the bony nostrils are never quite vertical, and the partition is always crowded toward the right, so as in some cases wholly to obliterate the nostril of that side. All our domesticated animals, too, are liable, like man, to a deficiency or redundancy of fingers and toes, and never to the same extent upon the two sides. The same is the case among birds, whose beaks also, especially when large, as in ducks, etc., are generally a little out of the straight line. In the curious crossbills, the lower beak curves strongly to one side, while the upper one curves as far to the other.

Among reptiles and fishes, the same things are found whenever they are looked for, but we have space for only a few striking examples. Cuvier has noticed that in salamanders the bones of the pelvis are sometimes attached to the backbone by the process of one vertebra on the one side and by that of a different one on the other, so that a slight obliquity is produced; and I am informed by Professor Agassiz, who has kindly supplied me with many facts and suggestions upon this subject, that a slight inequality often exists between the two sides of the lower shell or plastron of turtles. I do not know that any imperfections of symmetry have been observed with the ordinary fishes, whose mode of life certainly requires a most accurate balancing of the two sides of the body ; but many of the selachians, whose bodies tend toward a flattened and outspread form, present quite striking differences of color, form, and structure between the two sides.

The sunfish, too (not the jelly-fish, which is a radiate), swims wholly upon one side, which is white or light colored, while the other and upper side is dark. But it is among the flounders and their allies that the most extraordinary differences exist between the right and the left side. They, like the sunfish, swim always upon one side, which is in some species the right and in others the left ; but not only are the colors of these different, but the whole head is twisted so as to bring as much as possible upon the top ; and, most wonderful of all, the eye of the lower side actually looks out of the upper side close by its fellow, which properly belongs there ; — the nature of this extraordinary transmigration will be referred to under the next proposition.

As would be expected from their mode of locomotion, most of the internal organs of birds are more symmetrical than those of the mammalia ; their liver, for instance, instead of lying wholly upon the right side, consists of two nearly equal portions, one upon each side of the backbone ; but in some species the right lobe is decidedly the longer ; the lower larnyx, the true vocal organ of birds, lies not in the throat, but behind the end of the breast-bone; it is generally divided into two apparently equal halves, but in the swans and geese, etc., one side is very much larger than the other.

The lungs of all reptiles, when inflated, are seen to be quite different on the two sides ; and in the serpents one half is a mere rudiment, while the other is enormously developed, reaching a great distance along the cavity of the body.

For obvious reasons, it is much easier to detect imperfections of symmetry in the articulates than in the vertebrates. The markings of butterfly wings always present some slight difference upon the two sides. I am not aware that any observations have been made upon the size and length of the legs or antennæ, but it would be well worth while to make them, in view of what those organs exhibit among the next group, the Crustacea. In very many genera of crabs (Lithodus, Cardesonia, and the little fiddler crabs of the Southern marshes), one biting - claw is much larger than the other ; the same is true of the lobster (Astacus), and of some other genera (Gelasimus, etc.), while in Bopyrus, one entire side of the body is larger than the other.

Among the mollusks even an approach to symmetry is the exception, as in the cuttle-fishes, while the ordinary bivalve shells, even when quite symmetrical, always have the hinge-joint unequally divided between the two valves ; in the common oyster one valve is deeper than the other, and in a curious genus (Radiolites) the difference is so great as to suggest what happens to one valve among the so-called univalve shells, — its reduction to a mere flat plate to close the mouth of its now immensely enlarged and coiled fellow.

This is a pretty formidable array of instances of manifest departure from exact symmetry in the three types of the animal kingdom in which the body is composed of two halves, and we may now inquire into the direct means by which these deviations from symmetry are produced.

IV.

That in all cases of marked departure from symmetry in adult animals, a less deviation exists at an earlier period of development.

Professor Wyman has seen a young lobster, nearly three inches in length, in which the right and left anterior claws were still symmetrical, although this is one of the species in which, at a greater age, one claw is very much larger than the other. The same thing is true of the other Crustacea and of the mollusks, and even, incredible as it may seem, of the extraordinary cases among the vertebrates. In the young narwhal the right and left upper teeth were of equal size, but the former remains stationary and imbedded in its socket, while the left grows very fast and finally attains a length of several feet.

The very young flounder is as symmetrical and well balanced as any other fish ; but as it grows it swims more and more upon one side, and the lower surface remains light colored and the upper becomes dark; all its internal organs, even its brain, partake of the steadily increasing twist, and the eye of the lower side, according to the observation of Steenstrup, actually sinks inward, and gradually works its way through the softer parts, and passes through a place where there is no bone, and at last makes its appearance upon the other and upper surface of the head, not far from its mate ; but it always has an irregular, somewhat foreign look and position, so as to be easily distinguished from the original eye of that side. I know nothing of the differences between the embryonic limbs of animals as compared with the differences already alluded to as existing in the adult, but will repeat my belief that in all cases these differences were only less, not totally absent.

The changes which occur during development among the internal organs of most mammals, including man, are not less extensive and wonderful than those observed in the flounder. Without entering into details, it is enough to say, that all those organs, as the heart, the stomach, the liver, and the spleen, which in the adult lie more upon one than upon the other side of the middle line, and are irregular and unsymmetrical in shape, were in the embryo not only regular and symmetrical, but placed each upon the middle line of the body ; they were then sometimes smaller, sometimes proportionally larger, than at a later period, but the chief changes are in shape and position. The long and tortuous intestine was once a short, straight, and simple canal, the lungs were much less different, and the kidneys were more nearly symmetrical in form and position.

Even if the most careful embryologists had not become convinced of the above facts by the various stages as to form and position of the several viscera, as seen in embryos at different periods of development, there are certain other and more easily observed facts which would alone indicate that at some early stage the organs had a different aspect from that in the adult. Occasionally a man’s heart is found to he upon the middle line and directly beneath the breast-bone ; while cases are by no means rare of a reversed arrangement of organs, the heart lying upon and pointing toward the right side, the right lung being the longer and narrower, while the left is shorter, being pushed up by the liver, which has changed places with the stomach ; the latter, with the spleen and pancreas, lying in the right side of the abdomen.

V.

That deviations from symmetry ought eventually to be divided into three classes, which may be called Abnormal, Teleological, and Normal.

The first will include those exaggerated and exceptional differences between right and left sides which are produced by disordered action, and which result in disease or deformity.

The second, those more or less apparent deviations from symmetry which are connected with certain special needs of the organism in which they occur.

The third will include all other cases of imperfect symmetry which we cannot account for upon grounds of special adaptation or malformation, and which, we must believe, are due to the action of still higher laws, and to necessities above and beyond those now generally recognized.

I do not feel prepared to state my own belief as to the way in which all the facts above given are to be divided among these three classes ; but I am fully convinced that the distinctions ought to be drawn. That they are true to nature is more evident when we contrast striking examples of each together. The production of a club-foot upon one leg, or of a supernumerary finger upon one hand, or of a single cross-eye, is surely not normal, nor is it to be accounted for as conducive in any way to the comfort or well-being of the individual: on the other hand, the displacement of the abdominal viscera is evidently for convenience of packing in the smallest possible space ; the greater size of one claw enables the lobster to use it for offence and for crushing larger bodies, and the other as an organ for carrying food to the mouth. Under the same category ought, probably, to be placed those structural distinctions between the right and the left hands which enable us without reflection to use the one for one purpose and the other for another ; since, as Sir Charles Bell has remarked, delay would often be dangerous and sometimes fatal. All these and some other cases may clearly be regarded as wise provisions of the Creator for the sake of the individual ; and this conclusion is, perhaps, not incompatible with occasional reversions of the usual arrangements ; as in left-handed people, in those whose viscera are transposed, and in flat-fish, which are dark upon the right side, while the larger number of their species are dark upon the left.

But the third, and by far the most numerous class of cases, we are, at present at least, utterly unable to account for in either of the above ways. There are slight and almost imperceptible differences between the right and left sides of even the most regular faces, which certainly are not deformities, and which we have no reason to believe are especially adapted to the mere physical necessities of the individual ; the same is to be said of the differences in the markings of animals, of butterflies, and of beetles ; and of all the other deviations from perfect and ideal symmetry, whether in nature or in art, which the superficial artist or naturalist may overlook, which the arrogant and self-willed may ignore, but which the true lover of the beautiful humbly admits to exist, even though they seem to baffle his highest endeavors and to render imperfect the works of God himself.

VI.

That there are principles, natural, human, and Divine, which require that the more perfect and highly organized forms should consist of two similar halves separated by a mesial plane, but which at the same time forbid that these two similar halves should ever be absolutely identical.

Thus far all our argument has been inductive in its character; and no conclusions have been drawn without a tolerable support of undeniable facts. Perhaps the easier way of concluding the subject would be to express the above proposition as an individual opinion, the truth of which is made probable by the facts already presented. But while this is so, and while on merely natural grounds the proposition might be provisionally accepted, yet with even more reason might its validity be questioned, since it is impossible to demonstrate it upon all the objects of nature. But in addition to the evidence, partial as it is, afforded by the few observed facts in support of the universal operation of natural laws toward the production of duality in animals and their organs and in the leaves of plants, we may cite the opinions of philosophers who certainly derived a part of their inspiration from nature itself.

Oken, the greatest and most profound naturalist of his time, of whom Agassiz writes that he will never be forgotten so long as thinking is connected with investigation, says, “ Every single thing is a duplicity,” and “ all motion has resulted from a duplicity.” ¹ And were it necessary, whole pages of quotations could be given from the highest authorities, expressing their belief in the existence of symmetry and of natural laws which tend to produce it.

In evidence of the imperfection of this symmetry, I quote from a single author ; for although most writers on anatomy recognize the facts, they seldom express an opinion concerningmore than what is then being described.

The great Swedish philosopher, who was a most learned man of science, and fully recognized as such long before the publication of those theological works which have since induced disbelievers therein to look with suspicion upon his purely scientific labors, expresses himself in the following manner: " No society can exist among absolute peers or equals ; the founding of society involves a perpetual diversity of members.” He here refers directly to entire individuals, but the same idea is elsewhere expressed in treating of halves of a single individual. “ In order that all things may flow to and fro in a constant circle, and that each may be emulous of perpetuity and describe forms that shall perpetuate the motions of life, the viscera, cavities, and septa of the organic frame [of man] are not precisely equilibrated and sustained by each other in the manner of a wellpoised balance ; they are not symmetrical, nor of equal force and weight on the right and left sides of the body.” ²

So much for natural laws. That there are also spiritual laws and principles which correspond to and act by means of them is certainly not demonstrable upon natural grounds. But no such demonstration is needed by those wrho believe that all natural objects and laws and processes are merely the visible results and representatives of corresponding spiritual objects and Laws and processes ; who believe that the outer corporeal man is only the clothing of the inner and spiritual man, yet that the former is so fully and completely adapted to the latter that the constitution and function of the one may be surely concluded from the other ; who feel assured that the spirit of man has eyes and ears and the power of speech equally with the body; that it has arms and hands and legs and feet and all things belonging to them ; that it has what corresponds to the heart, to the lungs, to the stomach, and to the brain, yes, and to each and every part and organ of the brain ; and that finally, since the human body is composed of two halves, similar, yet not identical in structure, either consentaneous or independent in action, and thus mutually aiding each other and acting as one for all higher purposes of life,—as when we look with two eyes into the face of our friend, when we leap for joy to meet him, when not one but both hands clasp his, when our two arms meet around the beloved form, — therefore at the same time, and even when the bodily actions are impossible, do the parts of the soul look and hasten and grasp and hold what they can perceive in the unseen world. The soul also consists of two similar, yet not identical halves : the one, the will, including all affections and desires and loves of every kind ; the other, the understanding, including all thoughts and ideas and knowledges; for each desire upon the one side there is upon the other a corresponding faculty of thought in order to accomplish it; for everything we know there is a counterpart of affection to use that knowledge ; but affection is not thought, neither is desire the same as knowledge, or love the same as wisdom ; they correspond, they are similar, and, in one sense, equal, but never identical.

All this and more is expressly taught in the religious doctrines revealed through Swedenborg; and as we have already quoted from his scientific works in support of the natural laws of symmetry, let us now see what his theological writings say concerning the corresponding spiritual laws : —

“ The right of the body and of the brain relates to the good of love, whence comes the truth of wisdom ; and the left to the truth of wisdom from the good of love. And as the conjunction of good and truth is reciprocal, and that conjunction makes, as it were, a one, hence those pains act together and conjointly in their functions, motions, and senses.” ³

“The left part of the brain corresponds to things rational or intellectual, but the right to affections or things voluntary.” ⁴

And now, if all this is true, — and by a large and constantly increasing circle of readers it is fully believed, — then, since man was made in the image and likeness of God, in him too, or rather in his works and in the operations of his providence, we ought to seek for similar indications of a dual nature : the one perfect love, wishing the highest possible good to all men ; the other perfect wisdom, by means of which love acts to produce the effects it desires. Through men these two qualities flow down into the corresponding regions of their minds; through nature they come to us as the heat and light of the sun ; which, like them, are similar, yet distinct, may act together or independently, and may be either one in excess, but never in nature absolutely alone.

There are, of course, many questions connected with this subject which readily occur to the reader, but which are not so easily solved ; for most of them either require the most minute and careful search for slight anatomical differences between the two sides of the body, or involve an immense amount of statistical information upon the habits of men and animals, with a careful discrimination between those which are merely acquired, and thus exist in any given number of individuals in pretty equal proportions, and those which, being universal or nearly so, must be regarded as connected with some structural peculiarities, even when they cannot be detected in any other way.

The six propositions already advanced may not appear demonstrated, and perhaps the writer ought only to hope that the facts and ideas here given may incite others to further investigations upon this interesting topic.