Two Men of Mark

I

THE rose that is so venturous in spring as to come out with one petal more than normal inevitably has one stamen less. The plant breeder who finds that plant puts it aside and uses it to breed by. The rose in a state of nature has five petals and a multitude of stamens; that of the garden and conservatory has lost nearly all its stamens and has petals in profusion. The contrast between the two is all owing to this plasticity of parts. Between the simple rose of the woodside and the beauty of Shiraz there would seem to be a world of difference — but not to the eye of the scientist. In the change he sees a principle.

These reversions of stamen to petal are possible because stamen and petal, as well as other parts of the flower, were each developed, or evolved, out of a leaf. Herein we read a lesson in evolution. When the higher plants ceased to be all mosses or ferns and the like, and took on the modern sex method of propagation, a flower had to come into being. To make a flower there had to be a variety of parts — a calyx to protect and support the bloom, petals to attract the attention of flying insects by their color and perfume, stamens to produce the pollen or male principle, and a pistil with an enveloping carpel or womb to contain the ovule and act in the female capacity. Each of these essentials was developed out of a leaf.

The work was done by transformation, not creation. This is nature’s usual method. When she has a new thing to bring forth, she makes it out of something already on hand. We have never yet caught her in the act of creation; she is always making over. And as she makes, so she unmakes. Hence the ease with which the stamen ceases to be a male organ producing pollen and turns into a petal offering bribes to the bee.

The plant breeder cannot, of course, get this all done at once and to order. He is hardly on such intimate terms with nature. He has to watch and wait until nature, ever varying from her standards, produces something of the kind he wants; and then, by protecting this and interbreeding it with other plants of like tendency, he adds more and more to the result desired. While the cultivated rose is a ravishing combination of color and fragrance, it must be admitted that the wild rose, by sticking to its standard of few petals and much pollen, knows its business best. The tame rose has gone in wholly for publicity, and it has hardly anything to offer the insect that answers its advertisement.

After the rose let us examine the water lily. The water lily that we are considering has green sepals, white petals, and yellow stamens — that much is evident at a glance; but upon closer inspection we note that they pass into one another so gradually, through leaves that show all the intermediate stages, that we are puzzled to say just where one part of the flower begins and the other ends.

Here evolution seems to be caught in the act. It is an interesting illustration of each step in the process, not a man-made sequence or mere schematic arrangement. The nature student who turns the leaves of the water lily one by one will find that he is dealing at once with a flower and a book. It is a wordless little work on evolution.

Any change that Mother Nature may make is hardly so great as it looks. While she may be achieving all sorts of new functions and going in for new designs, she does it with the same old parts. Of the truth of this method there are no fairer witnesses than the water lily and the rose. The trillium, too, whose white blossom is so familiar in spring in protected woods, is worthy of a hearing. It usually has six stamens; but occasionally three will be found to have taken on a leaflike form.

The essential parts of a plant consisting of root, stem, and leaf, it seems natural for us to form the idea that a root always grows underground while the stem forms the upper structure and the leaves court the light and air. Nature is not nearly so conservative; she is not at all hampered by notions. A potato grows underground like a root, but it is really a stem that has been enlarged for purposes of food storage. That is why it grows buds, and has depressions that are the axils of incipient leaves. The sweet potato, on the other hand, is an enlarged root and has no such eyes or buds. An onion is a cluster of thick, food-storing leaves. A turnip is an enlarged taproot. A cactus would seem to have big, thick, waterstoring leaves, but such is not the case. What seems to be a leaf, with all the shape and greenness of a leaf, is really a stem. The sharp, protective spines on those stems are transformed leaves; and that is why it is possible to breed back to a spineless cactus.

For the support of vines that do not twine about a support, nature would seem to be in need of adding something new in the way of a tendril. Instead, we find her making things over to meet the new demand. The tendril of a grapevine is a modified stem, while that of a pea vine is a modified leaf. The poison ivy and the trumpet creeper cling to the wall by means of aerial rootlets. In the Solanum jasminoides, or ornamental potato vine, the leaves themselves act as tendrils by simply looping their stems about the slender support.

Any logical notion that this thing should always be used for this, and that thing for that, does not hold with nature. She is strong on makeshift and economy of means. Old parts fit new functions, and the methods are not at all orthodox.

II

The man who discovered and apprehended this principle in plant evolution was the poet Goethe, who died in 1832. He not only made independent discovery of the principle, but spent years in trying to get the facts recognized by the scientists of his day. Anything so open to investigation, and so suggestive to the mind of the thinker, would seem to need only to be enunciated in order to be gladly received. And when, in his forty-second year, he published his treatise on Metamorphosis in Plants, some progress seemed to him to be probable. But the world does not work that way. It has been well observed that the man and the moment must agree. Time and tide wait for no man — neither do they take a single extra step to catch up with him. Goethe, a poet, was too far ahead of the scientific procession. It is doubtful whether even so scientifically gifted and devoted a man as Darwin could have succeeded in making the idea of evolution take hold in that day. Scientific caste and tradition, and settled notions regarding the act of creation, were against it.

Goethe’s all-including mind did not confine itself to the subject of plants. He was quite as interested in the animal creation. To the anatomists of Goethe’s day it seemed that the upper jaw (maxilla) of man was a single, continuous bone, and therefore different in structure from that of the lower animals. In all of the other mammals, up to and including the apes, that part of the upper jaw which bears the incisors or cutting teeth is separate from the rest. Goethe, in spite of all evidence to the contrary, insisted that this separate premaxillary bone was to be found in man. He had come to believe in a certain unity and harmony in nature, and he was not willing to admit an exception of this kind.

The fact is that the maxilla is all in one piece, with no evidence of the bone having been knit together; and, when we consider this, Goethe’s case would seem to be a hard one. But at last he discovered and pointed out traces of such knitting together of bones on the inner side of the upper jaws of young children. This discovery, however, made no impression on the scientific world, either in regard to the fact itself or in regard to the principle involved. We now know that he was right. The study of embryology has shown the separate maxillary bone to have an existence at a stage of human development.

In evaluating Goethe’s discovery at this distant day, we should remember that he was concerned not merely about a detail of human anatomy, but about a principle in nature which he had somehow come to have faith in. That principle we now call by the name of evolution.

His great reputation as a man of letters was no help to his theories. When a man is firmly established in the character of poet, the public is hardly going to take his scientific pronouncements seriously. The world generally has its public characters neatly ticketed: a man is a poet, a scientist, or a philosopher; and this ‘a’ system is quite adequate to the cataloguing of the general run of men. It was not easy for his own generation to see that Goethe was a mentality which the word ‘a’ could hardly cover. He was a thinker in science — one who could take facts and see where they were leading. That is why Emerson said, in writing about him, that ‘eyes are better on the whole than telescopes and microscopes.’

III

In this year of the Goethe centenary — observance of which should hardly be confined to the republic of Germany — it does not seem to be remembered that the same year also marks the passing of the great founder of the science of comparative anatomy, Georges Cuvier. The two men, alike engaged with the methods and mysteries of nature, held views so exactly opposite that one becomes definitive of the other. The quickest way in which one could convey Goethe’s view of creation would be to compare it with that of Cuvier.

Cuvier believed that each living thing was a special creation perfectly designed by the Creator for the kind of life it was to lead. Each animal, therefore, has a perfect consistency within itself; there is a complete set of ‘correspondences’ between part and part. Cuvier’s eminence in his profession was all the outcome of his recognition of the fact that function determines structure. If a machine is to do a certain work, it must be built throughout in accordance with that requirement. Hence his saying, ‘Give me a tooth and I will reconstruct the whole animal.’

The pronouncement was hardly an exaggeration of his ability. Others before him had done creditable work in the study of animal structure; but Cuvier’s great grasp and systematization of the whole series of animal forms have made him justly considered the founder of the science.

One would naturally suppose that if there was one man to whom the evolutionary method of creation would strike home it would be the world’s greatest comparative anatomist. In the work of dividing animals into species, the naturalist is employed in noting differences, these differences being the basis of his classification. But when one begins to compare animals with any depth of observation he notes essential similarities; and finally these likenesses are so many and so fundamental that they begin to mean as much as do the differences. It was upon such observation that the idea of evolution took its rise.

Cuvier, with all his thoroughness, did not seem to note the likenesses. Vestigial organs, remnants of the past such as the splint bones of the horse, had no meaning and no message for him. This was in accordance with his philosophy that the Creator made each animal especially to fit its surroundings, and such work was necessarily perfect, with every detail essential.

In paleontology he was also a master, his knowledge of present forms enabling him to deal with the bones of animals that were extinct. In this field, in which he worked so intimately, one would expect that some notion of the methods of evolution would find entrance to his mind. Not only does the geological record show us animals that are extinct, but it yields up animals that first appear on earth rather late in the history of creation. We note also that there was an age of reptiles, when conditions on earth favored that form of life; and later on we see the rise of mammals.

What theory did Cuvier regard as meeting these facts? He simply believed that when God wanted another sort of animal He made it. This answer to him was sufficient. As for the appearance in the rocky record of a whole set of animals of a similar kind, how did he account for that? Here he held the cataclysmic theory. He said that all animals had been destroyed several times previous to the advent of Noah; and each time the Creator made a new set of animals such as He wanted to fit the new circumstances.

This explanation, taking Cuvier’s beliefs into account, was quite logical. His mind, like the animal structures he studied, was entirely consistent within itself. Our own Agassiz held to a like opinion.

IV

The theory of evolution advanced somewhat unevenly, by stops and starts, in the minds of a number of men — Buffon (1707-1788), Lamarck (1744-1829), Goethe(1749-1832), Geoffroy Saint-Hilaire (1772-1844), Darwin (1809-1882). We are prone to forget that even evolution had to evolve.

Goethe’s place in this procession of minds was not that of a mere adherent and yes-man of a full-fledged theory. He was an observer and thinker, and his basic contribution to botany and to comparative anatomy helped definitely to advance the scientific point of view. Before his death, in his eightythird year, his facts had won acceptance.

In his theory of the nature of light and color, in which he opposed Newton vigorously, he was wrong. But so also was Newton. The great Englishman’s corpuscular theory of light is now discountenanced. Goethe’s theory of the vertebral origin of the skull was brilliant and suggestive; it held its place in evolutionary theory until the more recent advances in embryology caused it to be displaced. These things show the scope of Goethe’s mind. As one of Emerson’s six Representative Men, he is put before us as the Writer — a well-considered classification which allows Shakespeare to stand forth as the Poet. But in according Goethe this particular preëminence we should not hold too narrow a view as to what a writer may be.

This making of a centenary out of a great man’s passing might seem to be putting emphasis in the wrong place. Why celebrate his death? The answer must be that we are commemorating the round period of time that has passed since he ended his work. We are taking account of ourselves, and measuring the progress we have made in that time.

It is the all-important present that engages us. ‘Creation continues.’ Today is always the high noon of history. It. is the last day of the past and the first day of the future. There is a verse in the Rig-Veda descriptive of dawn: —

In science it is always dawn.