Chapter 7: 1832-1834: Aet. 25-27.
- Enters upon his professorship at Neuchatel. -- first lecture. -- success as a teacher. -- love of teaching. -- influence upon the scientific life of Neuchatel. -- proposal from University of Heidelberg. -- proposal declined. -- threatened blindness. -- correspondence with Humboldt. -- marriage. -- invitation from Charpentier. -- invitation to visit England. -- Wollaston prize. -- first number of ‘Poissons Fossiles.’ -- review of the work.
The following autumn Agassiz assumed the duties of his professorship at Neuchatel. His opening lecture ‘Upon the Relations between the different branches of Natural History and the then prevailing tendencies of all the Sciences’ was given on the 12th of November, 1832, at the Hotel de Ville. Judged by the impression made upon the listeners as recorded at the time, this introductory discourse must have been characterized by the same broad spirit of generalization which marked Agassiz's later teaching. Facts in his hands fell into their orderly relation as parts of a connected whole, and were never presented  merely as special or isolated phenomena. From the beginning his success as an instructor was undoubted. He had, indeed, now entered upon the occupation which was to be from youth to old age the delight of his life. Teaching was a passion with him, and his power over his pupils might be measured by his own enthusiasm. He was intellectually, as well as socially, a democrat, in the best sense. He delighted to scatter broadcast the highest results of thought and research, and to adapt them even to the youngest and most uninformed minds. In his later American travels he would talk of glacial phenomena to the driver of a country stage-coach among the mountains, or to some workman, splitting rock at the road-side, with as much earnestness as if he had been discussing problems with a brother geologist; he would take the common fisherman into his scientific confidence, telling him the intimate secrets of fish-structure or fish-embryology, till the man in his turn grew enthusiastic, and began to pour out information from the stores of his own rough and untaught habits of observation. Agassiz's general faith in the susceptibility of the popular intelligence, however untrained, to the highest truths of nature, was  contagious, and he created or developed that in which he believed. In Neuchatel the presence of the young professor was felt at once as a new and stimulating influence. The little town suddenly became a centre of scientific activity. A society for the pursuit of the natural sciences, of which he was the first secretary, sprang into life. The scientific collections, which had already attained, under the care of M. Louis Coulon, considerable value, presently assumed the character and proportions of a wellor-dered museum. In M. Coulon Agassiz found a generous friend and a scientific colleague who sympathized with his noblest aspirations, and was ever ready to sustain all his efforts in behalf of scientific progress. Together they worked in arranging, enlarging, and building up a museum of natural history which soon became known as one of the best local institutions of the kind in Europe. Beside his classes at the gymnasium, Agassiz collected about him, by invitation, a small audience of friends and neighbors, to whom he lectured during the winter on botany, on zoology, on the philosophy of nature. The instruction was of the most familiar and informal character, and was continued in later  years for his own children and the children of his friends. In the latter case the subjects were chiefly geology and geography in connection with botany, and in favorable weather the lessons were usually given in the open air. One can easily imagine what joy it must have been for a party of little playmates, boys and girls, to be taken out for long walks in the country over the hills about Neuchatel, and especially to Chaumont, the mountain which rises behind it, and thus to have their lessons, for which the facts and scenes about them furnished subject and illustration, combined with pleasant rambles. From some high ground affording a wide panoramic view Agassiz would explain to them the formation of lakes, islands, rivers, springs, water-sheds, hills, and valleys. He always insisted that physical geography could be better taught to children in the vicinity of their own homes than by books or maps, or even globes. Nor did he think a varied landscape essential to such instruction. Undulations of the ground, some contrast of hill and plain, some sheet of water with the streams that feed it, some ridge of rocky soil acting as a water-shed, may be found everywhere, and the relation of facts shown perhaps as well on a small as on a large scale.  When it was impossible to give the lessons out of doors, the children were gathered around a large table, where each one had before him or her the specimens of the day, sometimes stones and fossils, sometimes flowers, fruits, or dried plants. To each child in succession was explained separately what had first been told to all collectively. When the talk was of tropical or distant countries pains were taken to procure characteristic specimens, and the children were introduced to dates, bananas, cocoa-nuts, and other fruits, not easily to be obtained in those days in a small inland town. They, of course, concluded the lesson by eating the specimens, a practical illustration which they greatly enjoyed. A very large wooden globe, on the surface of which the various features of the earth as they came up for discussion could be shown, served to make them more clear and vivid. The children took their own share in the instruction, and were themselves made to point out and describe that which had just been explained to them. They took home their collections, and as a preparation for the next lesson were often called upon to classify and describe some unusual specimen by their own unaided efforts. There was no tedium in the class. Agassiz's  lively, clear, and attractive method of teaching awakened their own powers of observation in his little pupils, and to some at least opened permanent sources of enjoyment. His instructions to his older pupils were based on the same methods, and were no less acceptable to them than to the children. In winter his professional courses to the students were chiefly upon zoology and kindred topics; in the summer he taught them botany and geology, availing himself of the fine days for excursions and practical instruction in the field. Professor Louis Favre, speaking of these excursions, which led them sometimes into the gorges of the Seyon, sometimes into the forests of Chaumont, says: ‘They were fete days for the young people, who found in their professor an active companion, full of spirits, vigor, and gayety, whose enthusiasm kindled in them the sacred fire of science.’ It was not long before his growing reputation brought him invitations from elsewhere. One of the first of these was from Heidelberg.
Agassiz's next letter to Humboldt is to consult him with respect to the call from Heidelberg, while it is also full of pleasure at the warm welcome extended to him in Neuchatel.
Regarding the invitation to Heidelberg, Agassiz's decision was already made. A letter to his brother toward the close of December mentions that he is offered a professorship at the University of Heidelberg, but that, although his answer has not actually gone, he has resolved to decline it; adding that the larger salary is counterbalanced in his mind by the hope of selling his collection at Neuchatel, and thus freeing himself from a heavy burden. Agassiz was now threatened with a great misfortune. Already, in Paris, his eyes had begun to suffer from the strain of microscopic work. They now became seriously impaired;  and for some months he was obliged to abate his activity, and to refrain even from writing a letter. During this time, while he was shut up in a darkened room, he practiced the study of fossils by touch alone, using even the tip of the tongue to feel out the impression, when the fingers were not sufficiently sensitive. He said he was sure at the time that he could bring himself in this way to such delicacy of touch that the loss of sight would not oblige him to abandon his work. After some months his eyes improved, and though at times threatened with a return of the same malady, he was able, throughout life, to use his eyes more uninterruptedly than most persons. His lectures, always delivered extemporaneously, do not seem to have been suspended for any length of time. The following letter from Agassiz to Humboldt is taken from a rough and incomplete draught, which was evidently put aside (perhaps on account of the trouble in his eyes), and only completed in the following May. Although imperfect, it explains Humboldt's answer, which is not only interesting in itself, but throws light on Agassiz's work at this period. 
 In October, 1833, Agassiz's marriage to Cecile Braun, the sister of his life-long friend, Alexander Braun, took place. He brought his wife home to a small apartment in Neuchatel, where they began their housekeeping after the simplest fashion, with such economy as their very limited means enforced. Her rare artistic talent, hitherto devoted to her brother's botanical pursuits, now found a new field. Trained to accuracy in drawing objects of Natural History, she had an artist's eye for form and color. Some of the best drawings in the Fossil Fishes and the Fresh-Water Fishes are from her hand. Throughout the summer, notwithstanding the trouble in his eyes, Agassiz had been still pressing on these works. His two artists, Mr. Dinkel and Mr. Weber, the former in Paris, the latter in Neuchatel, were constantly busy on his plates. Although Agassiz was at this time only twenty-six years of age, his correspondence already shows that the interest of scientific men, all over Europe, was attracted to him and to his work. From investigators of note in his own country, from those of France, Italy, and Germany, from England, and even from America, the distant El Dorado of naturalists in those days, came offers of cooperation,  accompanied by fossil fishes or by the drawings of rare or unique specimens. He was known in all the museums of Europe as an indefatigable worker and collector, seeking everywhere materials for comparison. Among the letters of this date is one from Charpentier, one of the pioneers of glacial investigation, under whose auspices, two years later, Agassiz began his inquiries into glacial phenomena. He writes him from the neighborhood of Bex, his home in the valley of the Rhone, the classic land of glacial work; but he writes of Agassiz's special subjects, inviting him to come and see such fossils as were to be found in his neighborhood, and to investigate certain phenomena of upheaval and of plutonic action in the same region, little dreaming that the young zoologist was presently to join him in his own chosen field of research. Agassiz now began also to receive pressing invitations from the English naturalists, from Buckland, Lyell, Murchison, and others, to visit England, and examine their wonderful collections of fossil remains. 
A few months later Agassiz received a very gratifying and substantial mark of the interest felt by English naturalists in his work.
 The first number of the ‘Fossil Fishes’ had already appeared, and had been greeted with enthusiasm by scientific men. Elie de Beaumont writes Agassiz in June, 1834: ‘I have read with great pleasure your first number; it promises us a work as important for science as it is remarkable in execution. Do not let yourself be discouraged by obstacles of any kind; they will give way before the concert of approbation which so excellent a work will awaken. I shall always be glad to aid in overcoming any one of them.’ Perhaps it is as well to give here a slight sketch of this work, the execution of which was carried on during the next ten years (1833-1843). The inscription tells, in few words, the author's reverence for Humboldt and his personal gratitude to him. ‘These pages owe to you their existence; accept their dedication.’ The title gives in a broad outline the comprehensive purpose of the work: ‘Researches on the Fossil Fishes: comprising an Introduction to the Study of these Animals; the Comparative Anatomy of Organic Systems which may contribute to facilitate the Determination of Fossil Species; a New Classification of Fishes expressing their Relations to the Series of Formations; the Explanation of  the Laws of their Succession and Development during all the Changes of the Terrestrial Globe, accompanied by General Geological Considerations; finally, the Description of about a thousand Species which no longer exist, and whose Characters have been restored from Remains contained in the Strata of the Earth.’ The most novel results comprised in this work were: first, the remodeling of the classification of the whole type of fishes, fossil and living, and especially the separation of the Ganoids from all other fishes, under the rank of a distinct order; second, the recognition of those combinations of reptilian and birdlike characters in the earlier geological fishes, which led the author to call them prophetic types; and third, his discovery of an analogy between the embryological phases of the higher present fishes and the gradual introduction of the whole type on earth, the series in growth and the series in time revealing a certain mutual correspondence. As these comprehensive laws have thrown light upon other types of the animal kingdom beside that of fishes, their discovery may be said to have advanced general zoology as well as ichthyology.  The Introduction presents, as it were, the prelude to this vast chapter of natural history in the simultaneous appearance of the four great types of the animal kingdom: Radiates, Mollusks, Articulates, and Vertebrates. Then comes the orderly development of the class by which the vertebrate plan was first expressed, namely, the fishes. Underlying all its divisions and subdivisions, is the average expression of the type in the past and present; the Placoids and Ganoids, with their combination of reptilian and fishlike features, characterizing the earlier geological epochs, while in the later the simple bony fishes, the Cycloids and Ctenoids, take the ascendency. Here, for the first time, Agassiz presents his ‘synthetic or prophetic types,’ namely, early types embracing, as it were, in one large outline, features afterward individualized in special groups, and never again reunited. No less striking than these general views of structural relations are the clearness and simplicity with which the distribution of the whole class of fishes in relation to the geological formations, or, in other words, to the physical history of the earth, is shown. In reading this introductory chapter, one familiar with Agassiz as a public teacher will almost hear his voice marshaling the long  procession of living beings, as he was wont to do, in their gradual introduction upon the earth. Indeed, his whole future work in ichthyology, and one might almost say in general zoology, was here sketched. The technicalities of this work, at once so comprehensive in its combinations and so minute in its details, could interest only the professional reader, but its generalizations may well have a certain attraction for every thoughtful mind. It treats of the relations, anatomical, zoological, and geological, between the whole class of fishes, fossil and living, illustrated by numerous plates, while additional light is thrown on the whole by the revelations of embryology. ‘Notwithstanding these striking differences,’ says the author in the opening of the fifth chapter on the relations of fishes in general, ‘it is none the less evident to the attentive observer that one single idea has presided over the development of the whole class, and that all the deviations lead back to a primary plan, so that even if the thread seem broken in the present creation, one can reunite it on reaching the domain of fossil ichthyology.’6 Having shown how the present creation has  given him the key to past creations, how the complete skeleton of the living fishes has explained the scattered fragments of the ancient ones, especially those of which the soft cartilaginous structure was liable to decay, he presents two modes of studying the type as a whole; either in its comparative anatomy, including in the comparison the whole history of the type, fossil and living, or in its comparative embryology. ‘The results,’ he adds, ‘of these two methods of study complete and control each other.’ In all his subsequent researches indeed, the history of the individual in its successive phases went hand in hand with the history of the type. He constantly tested his zoological results by his embryological investigations. After a careful description of the dorsal chord in its embryological development, he shows that a certain parallelism exists between the comparative degrees of development of the vertebral column in the different groups of fishes, and the phases of its embryonic development in the higher fishes. Farther on he shows a like coincidence between the development of the system of fins in the different groups of fishes, and the gradual growth and differentiation of the fins in the embryo of the  higher living fishes.7 ‘There is, then,’ he concludes, ‘as we have said above, a certain analogy, or rather a certain parallelism, to be established between the embryological development of the Cycloids and Ctenoids, and the genetic or paleontological development of the whole class. Considered from this point of view, no one will dispute that the form of the caudal fin is of high importance for zoological and paleontological considerations, since it shows that the same thought, the same plan, which presides to-day over the formation of the embryo, is also manifested in the successive development of the numerous creation which have formerly peopled the earth.’ Agassiz says himself in his Preface: ‘I have succeeded in expressing the laws of succession and of the organic development of fishes during all geological epochs; and science may henceforth, in seeing the changes of this class from formation to formation, follow the progress of organization in one great division of the animal kingdom, through a complete series of the ages of the earth.’ This is not inconsistent with his position as the leading opponent of the development or Darwinian  theories. To him, development meant development of plan as expressed in structure, not the change of one structure into another. To his apprehension the change was based upon intellectual, not upon material causes. He sums up his own conviction with reference to this question as follows:
The difficulty of carrying out comparisons so rigorous and extensive as were needed in order to reconstruct the organic relations between  the fossil fishes of all geological formations and those of the present world, is best told by the author.8 ‘Possessing no fossil fishes myself, and renouncing forever the acquisition of collections so precious, I have been forced to seek the materials for my work in all the collections of Europe containing such remains; I have, therefore, made frequent journeys in Germany, in France, and in England, in order to examine, describe, and illustrate the objects of my researches. But notwithstanding the cordiality with which even the most precious specimens have been placed at my disposition, a serious inconvenience has resulted from this mode of working, namely, that I have rarely been able to compare directly the various specimens of the same species from different collections, and that I have often been obliged to make my identification from memory, or from simple notes, or, in the more fortunate cases, from my drawings only. It is impossible to imagine the fatigue, the exhaustion of all the faculties, involved in such a method. The hurry of traveling, joined to the lack of the most ordinary facilities for observation, has not rendered my task more  easy. I therefore claim indulgence for such of my identifications as a later examination, made at leisure, may modify, and for descriptions which sometimes bear the stamp of the precipitation with which they have been prepared.’ It was, perhaps, this experience of Agassiz's earlier life which made him so anxious to establish a museum of comparative zoology in this country,—a museum so abundant and comprehensive in material, that the student should not only find all classes of the animal kingdom represented within its walls, but preserved also in such numbers as to allow the sacrifice of many specimens for purposes of comparison and study. He was resolved that no student should stand there baffled at the door of knowledge, as he had often done himself, when shown the one precious specimen, which could not be removed, or even examined on the spot, because unique.
Such facts proclaim aloud principles not yet discussed in science, but which paleontological researches place before the eyes of the observer with an ever-increasing persistency. I speak of the relations of the creation with the creator. Phenomena closely allied in the order of their succession, and yet without sufficient cause in themselves for their appearance; an infinite diversity of species without any common material bond, so grouping themselves as to present the most admirable progressive development to which our own species is linked,— are these not incontestable proofs of the existence of a superior intelligence whose power alone could have established such an order of things? . . .More than fifteen hundred species of fossil fishes, which I have learned to know, tell me that species do not pass insensibly one into  another, but that they appear and disappear unexpectedly, without direct relations with their precursors; for I think no one will seriously pretend that the numerous types of Cycloids and Ctenoids, almost all of which are contemporaneous with one another, have descended from the Placoids and Ganoids. As well might one affirm that the Mammalia, and man with them, have descended directly from fishes. All these species have a fixed epoch of appearance and disappearance; their existence is even limited to an appointed time. And yet they present, as a whole, numerous affinities more or less close, a definite coordination in a given system of organization which has intimate relations with the mode of existence of each type, and even of each species. An invisible thread unwinds itself throughout all time, across this immense diversity, and presents to us as a definite result, a continual progress in the development of which man is the term, of which the four classes of vertebrates are intermediate forms, and the totality of invertebrate animals the constant accessory accompaniment.Recherches sur les Poissons Fossiles, vol. i. chapter VI. pp. 171, 172. Essay on the classification of fishes.