Three other books influenced Haeckel in his school-days, besides the works of Goethe. The first was Humboldt’s Aspects of Nature. This is another work that has had an effect on all the sensitive spirits of the nineteenth century. It is most unjustly depreciated by the young, blasé generation of our time, which dislikes the older style. In the first two volumes of the Cosmos we see the play of a great mind wherever we look for it.
Then came Darwin’s Naturalist’s Voyage round the World. The ardent youth had as yet on suspicion what the name would one day mean to him. Darwin was then regarded as a completed work on which final judgment had been rendered. He was appreciated as a traveller, a student of the geology of South America, and especially as the gifted investigator of the wonderful coral reefs of the Indian Ocean. His name stood thus in all the manuals, close even to that of Humboldt. Probably the young reader thought he had died long before. At all events, no one had a presentiment that this quiet naturalist and student of corals was about to light a torch that would flame over the world. The chief advantage that Haeckel drew from the two works was an ardent desire to see the tropics, with their virgin forests and blue coral seas. It has come to so many after reading these works, and persisted in their lives as the vivid image of a dream, like that which drove Goethe to Italy—the dream of a home of the soul that must one day be sought.
The third book was Schleiden’s The Plant and its Life. Matthias Jacob Schleiden was then in the best of his power, and had an influence that amounted to fascination on many of the younger men. Behind him lay a terrible struggle. He had begun his career as a lawyer, and had been so unfortunate that he even attempted his life. With his interest in botany a new life began, and he worked with the energy of one raised from the dead. He was certainly an original thinker. His name is known to us to-day especially as the founder of the cell-theory. This is the greatest distinction that he has earned. But at that time he had a much more general importance as a leader in the struggle to introduce a certain method of scientific research. A somewhat obscure epoch was coming to a close, a more or less superficial natural philosophy having sought to replace sound investigation. The struggle had ended with the decisive victory of the simple discovery of facts. There was everywhere a vague feeling that the progress of science was best secured by a bald enumeration and registration of bones, of the joints in the limbs of insects, or of pollen-filaments, rather than by the romantic and spirited leaps of natural philosophy over all the real problems into the heavens above. The question now arose whether this narrow method really exhausted the nature of things; whether scientific specialism, with its laurels of victory, would not prove in the end an equally dangerous enemy. What was “better” for the time being might be very far from really “good.” It was here that Schleiden stepped in. He fought against the prevailing specialism, at first in his own particular province of botany. He did not, indeed, take up the cause of the exploded pyrotechnics of the older natural philosophy, but pleaded for more general critical-philosophical methods. These must be preserved in any circumstances. The great botanist, he said, is not the man who can determine ten thousand species of plants according to the received models, but the man of clear logic and wide deductions from his lore. Botany must be conceived as a distinct branch of general thought; otherwise it is worthless, and its herbarium may rot unnoticed in the corner and its discoveries be the outcome of blind hazard. Schleiden himself had no perception of the great idea that Darwin was to bring into his province afterwards—the idea of the variability of species and of evolution, which brought to a critical stage the question whether the botanist was to be merely a subordinate museum-secretary or a creative thinker, a prophet of nature to whom plants would be part of a general philosophy, a part of God in the ideal sense of evolution. Yet Schleiden’s simple warning cry made a deep impression on many of the young men especially. There was a note of aspiration in it, an assurance that they were waiting for a sun that must rise somewhere. He was a master of language. There was the stuff of the poet in him. His works strayed out far beyond the range of his own province. Haeckel himself did the same work in later years. It is no wonder that Schleiden had a magical influence over him. In this case, indeed, it seemed as if the attraction was to determine his own career.
Schleiden taught botany at Jena University. Haeckel was still in the higher forms of his school at Merseburg, and remained there when his father resigned his position in the State service, and eventually removed to Berlin. At this time the ardent botanist decided to adopt the science of plants as his life-study when his final examination was over. Schleiden would teach him how to combine philosophy with botany. Then he would try to roam over the world as a practical botanist and visit the far-off zones where Mother Earth poured out her cornucopia of forms so generously.
While still in the higher form at school he made a preliminary visit to Jena. Everything seemed so pleasant and charming. He made the journey on foot. These long walks have always been his pride—to start out like a travelling scholar, with hardly anything in his pocket, to live on bread and water, and sleep in the hay at night; but to enjoy to the full all the incomparable delights that the great magician, nature, provides for the faithful novice—scenery, beautiful orchids, thoughts of God, Goethe, and the world. It was in 1849 that he visited Jena. He has described it himself: “After I had reverently admired the Goethe-room in the castle of Dornburg, I wandered, on a hot July day, over the shady meadows to Jena, singing lustily with my gay comrades. As I entered the venerable old market-place I found a troop of lively students in front of the Burgkeller, with coloured caps and long pipes, singing, and drinking the famous Lichtenhain beer from wooden tankards. It made a great impression on me, and as I took a tankard with them I made up my mind that I would some day be one of them.”
CHAPTER II
AT THE UNIVERSITY
It was botany itself that thwarted all these designs. The examination had passed off happily. Rooms were taken at Jena, at the Easter of 1852, for the advanced study under Schleiden. Then the indefatigable collector had an adventure on a cold March day. He spent hours in the wet meadows by the river Saale, searching for a rare plant, the squill (Scilla bifolia). He met with the fate of the angler in the story, who fell into the water in his haste to secure his big pike. He landed the fish, but not himself. The plant was found, but Haeckel’s zeal was punished with a severe rheumatism. He had to go home to his parents at Berlin to be tended. At Berlin he begins his studies, and the event to some extent decides his career. It would now be many years before he would see Jena again; and through his efforts it would become one of the leading schools, not of botany, but of zoology—a school of philosophical zoology, however, in the sense of Schleiden.
Berlin had secured a botanist of the first rank a year before, Alexander Braun. He, too, was a thoughtful botanist, who would in his way agree very well with Schleiden. He was convinced that botany did not wholly consist in the determination of new plant forms and the almost fruitless effort to set up a system on which all particular diagnoses would be rigidly played as on a piano. He believed that there must be a more profound conception of it, which would take “form,” as such, as one of its problems, and would aim, not at the formation of as large a collection as possible, but at the construction of a science for which Goethe had long ago found a name—morphology, or the science of forms. It happened that Braun was a friendly visitor at the house of Haeckel’s parents at Berlin. The now convalescent freshman became devoted to him, body and soul; they became close friends, not merely master and pupil. Berlin at that time afforded many an opportunity for practical botanising. Rare marsh-plants then flourished in the bed of the Spree, which has since been cleared. The Botanical Garden was full of good things. Haeckel used to tell with pride, long afterwards, with what readiness he flung himself into the work, practical as well as theoretical, on these excursions with Professor Braun. “On one of our botanical expeditions we wanted to get a floating chara from a pond. Braun took off his boots in his usual way in order to wade to the spot. But I was before him. I quickly undressed, forgot my naughty rheumatism, and swam to the spot, to bring him a quantity of the plant he wanted. That was my first piece of heroism, perhaps my greatest.”
But in all this pleasant botanising there was no serious outlook on his future profession. Haeckel’s father, with his official way of looking at things, could not reconcile himself to scientific research as an avocation. It is an old belief that the way to all preoccupation with the science of living things lies through medicine. One may question that to-day. It was the rock on which Darwin nearly came to grief. A man may be a very gifted botanist, yet be quite unfitted for the medical profession. One must have a real vocation to become a physician, more than for any other calling, or else it is a hopeless blunder. The talents are divided in much the same way as between the historian and the soldier. It is true that the two may be united, but it is equally true that very good historians have made very poor soldiers. What the medical man learns in his studies is, of course, always valuable. But it offers no test of personal talent for scientific research, nor should it be supposed that a capacity of this kind would be able, by mere formal study, to acquire the true qualities of a physician. We must learn to appreciate the physician’s calling too much ever to look on it as an incidental occupation. It always reminds me of the amiable notion of the Philistine, that a man with a turn for poetry must first take up some solid profession, and then, once he is “in the saddle,” pour out verses in his leisure hours. Poetry can never be a mistress: it demands marriage or nothing. Otherwise—well, we have instances enough.