I do not live the less happily on account of my anxieties, but I am sometimes obliged to work more than I well can, or ought in reason to do. . .The second number of my "Fossil Fishes" contains the beginning of the anatomy of the fishes, but only such portions as are to be found in the fossil state. I have begun with the scales; later, I treat of the bones and the teeth. Then comes the continuation of the description of the Ganoids and the s...o...b..roids, and an additional sheet contains a sketch of my ichthyological cla.s.sification. The plates are even more successful than those of the first number. If all goes well the third number will appear next July. I long to visit your rich collections; I hope that whenever it becomes possible for me to do so, I shall have the good fortune to find you in London. . .
I have thought a letter addressed to the President of the Society in particular, and to the members in general, would be fitting.
Will you have the kindness to deliver it for me to Mr. Murchison?
The first number of the "Fossil Fishes" had already appeared, and had been greeted with enthusiasm by scientific men. Elie de Beaumont writes Aga.s.siz 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 grat.i.tude to him. "These pages owe to you their existence; accept their dedication." The t.i.tle 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 Cla.s.sification 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 cla.s.sification 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 bird-like characters in the earlier geological fishes, which led the author to call them prophetic types; and third, his discovery of an a.n.a.logy 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 cla.s.s 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 ascendancy. Here, for the first time, Aga.s.siz 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 cla.s.s 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 Aga.s.siz 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 cla.s.s of fishes, fossil and living, ill.u.s.trated 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 cla.s.s, 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."* (*
Volume 1 chapter 5 pages 92, 93.)
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.* (* "Recherches sur les Poissons Fossiles", volume 1 chapter 5 page 102.) "There is, then," he concludes, "as we have said above, a certain a.n.a.logy, 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 cla.s.s. 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." Aga.s.siz 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 cla.s.s 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:* (* "Recherches sur les Poissons Fossiles" volume 1 chapter 6 pages 171, 172. "Essay on the Cla.s.sification of Fishes.") "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 pa.s.s 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 an other, 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 cla.s.ses of vertebrates are intermediate forms, and the totality of invertebrate animals the constant accessory accompaniment."
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.* (*
"Recherches sur les Poissons Fossiles" volume 1. Addition a la Preface.) "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 ill.u.s.trate 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 Aga.s.siz"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 cla.s.ses 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.
CHAPTER 8.
1834-1837: AGE 27-30.
First Visit to England.
Reception by Scientific Men.
Work on Fossil Fishes there.
Liberality of English Naturalists.
First Relations with American Science.
Farther Correspondence with Humboldt.
Second Visit to England.
Continuation of "Fossil Fishes."
Other Scientific Publications.
Attention drawn to Glacial Phenomena.
Summer at Bex with Charpentier.
Sale of Original Drawings for "Fossil Fishes."
Meeting of Helvetic Society.
Address on Ice-Period.
Letters from Humboldt and Von Buch.
In August, 1834, according to his cherished hope, Aga.s.siz went to England, and was received by the scientific men with a cordial sympathy which left not a day or an hour of his short sojourn there unoccupied. The following letter from Buckland is one of many proffering hospitality and friendly advice on his arrival.
DR. BUCKLAND TO LOUIS AGa.s.sIZ.
OXFORD, August 26, 1834.
. . .I am rejoiced to hear of your safe arrival in London, and write to say that I am in Oxford, and that I shall be most happy to receive you and give you a bed in my house if you can come here immediately. I expect M. Arago and Mr. Pentland from Paris tomorrow (Wednesday) afternoon. I shall be most happy to show you our Oxford Museum on Thursday or Friday, and to proceed with you toward Edinburgh. Sir Philip Egerton has a fine collection of fossil fishes near Chester, which you should visit on your road. I have partly engaged myself to be with him on Monday, September 1st, but I think it would be desirable for you to go to him Sat.u.r.day, that you may have time to take drawings of his fossil fishes.
I cannot tell certainly what day I shall leave Oxford until I see M. Arago, whom I hope you will meet at my house, on your arrival in Oxford. I shall hope to see you Wednesday evening or Thursday morning. Pray come to my house in Christ Church, with your baggage, the moment you reach Oxford. . .
Aga.s.siz always looked back with delight on this first visit to Great Britain. It was the beginning of his life-long friendship with Buckland, Sedgwick, Murchison, Lyell, and others of like pursuits and interests. Made welcome in many homes, he could scarcely respond to all the numerous invitations, social and scientific, which followed the Edinburgh meeting.
Guided by Dr. Buckland, to whom not only every public and private collection, but every rare specimen in the United Kingdom, seems to have been known, he wandered from treasure to treasure. Every day brought its revelation, until, under the acc.u.mulation of new facts, he almost felt himself forced to begin afresh the work he had believed well advanced. He might have been discouraged by a wealth of resources which seemed to open countless paths, leading he knew not whither, but for the generosity of the English naturalists who allowed him to cull, out of sixty or more collections, two thousand specimens of fossil fishes, and to send them to London, where, by the kindness of the Geological Society, he was permitted to deposit them in a room in Somerset House. The ma.s.s of materials once sifted and arranged, the work of comparison and identification became comparatively easy. He sent at once for his faithful artist, Mr.
d.i.n.kel, who began, without delay, to copy all such specimens as threw new light on the history of fossil fishes, a work which detained him in England for several years.
Aga.s.siz made at this time two friends, whose sympathy and cooperation in his scientific work were invaluable to him for the rest of his life. Sir Philip Egerton and Lord Cole (Earl of Enniskillen) owned two of the most valuable collections of fossil fishes in Great Britain.* (* Now the property of the British Museum.) To aid him in his researches, their most precious specimens were placed at Aga.s.siz"s disposition; his artist was allowed to work for months on their collections, and even after Aga.s.siz came to America, they never failed to share with him, as far as possible, the advantages arising from the increase of their museums. From this time his correspondence with them, and especially with Sir Philip Egerton, is closely connected with the ever-growing interest as well as with the difficulties of his scientific career. Reluctantly, and with many a backward look, he left England in October, and returned to his lectures in Neuchatel, taking with him such specimens as were indispensable to the progress of his work. Every hour of the following winter which could be spared from his lectures was devoted to his fossil fishes.
A letter of this date from Professor Silliman, of New Haven, Connecticut, marks the beginning of his relations with his future New England home, and announces his first New England subscribers.
YALE COLLEGE NEW HAVEN, UNITED STATES OF NORTH AMERICA, April 22, 1835.
. . .From Boston, March 6th, I had the honor to thank you for your letter of January 5th, and for your splendid present of your great work on fossil fishes--livraison 1-22--received, with the plates. I also gave a notice of the work in the April number of the Journal*
(* "The American Journal of Science and Arts".) (this present month), and republished Mr. Bakewell"s account of your visit to Mr.
Mantell"s museum.
In Boston I made some little efforts in behalf of your work, and have the pleasure of naming as follows:--
Harvard University, Cambridge (Cambridge is only four miles from Boston), by Hon. Josiah Quincy, President.
Boston Athenaeum, by its Librarian.
Benjamin Green, Esquire, President of the Boston Natural History Society.
I shall make application to some other inst.i.tutions or individuals, but do not venture to promise anything more than my best exertions . . .
Aga.s.siz little dreamed, as he read this letter, how familiar these far-off localities would become to him, or how often, in after years, he would traverse by day and by night the four miles which lay between Boston and his home in Cambridge.
Aga.s.siz still sought and received, as we see by the following letter, Humboldt"s sympathy in every step of his work.
HUMBOLDT TO LOUIS AGa.s.sIZ.
BERLIN, May, 1835.
I am to blame for my neglect of you, my dear friend, but when you consider the grief which depresses me,* (* Owing to the death of his brother, William von Humboldt.) and renders me unfit to keep up my scientific connections, you will not be so unkind as to bear me any ill-will for my long silence. You are too well aware of my high esteem for your talents and your character--you know too well the affectionate friendship I bear you--to fear for a moment that you could be forgotten.
I have seen the being I loved most, and who alone gave me some interest in this arid land, slowly decline. For four long years my brother had suffered from a weakness of all the muscles, which made me always fear that the seat of the trouble was the medulla oblongata. Yet his step was firm; his head was entirely clear. The higher intellectual faculties retained all their energy. He was engaged from twelve to thirteen hours a day on his works, reading or rather dictating, for a nervous trembling of the hand prevented him from using a pen. Surrounded by a numerous family; living on a spot created, so to speak, by himself, and in a house which he had adorned with antique statues; withdrawn also from affairs, he was still attached to life. The illness which carried him off in ten days--an inflammation of the chest--was but a secondary symptom of his disease. He died without pain, with a strength of character and a serenity of mind worthy of the greatest admiration. It is cruel to see so n.o.ble an intelligence struggle during ten long days against physical destruction. We are told that in great grief we should turn with redoubled energy to the study of nature. The advice is easy to give; but for a long time even the wish for distraction is wanting.
My brother leaves two works which we intend to publish: one upon the languages and ancient Indian civilization of the Asiatic archipelago, and the other upon the structure of languages in general, and the influence of that structure upon the intellectual development of nations. This last work has great beauty of style.
We shall soon begin the publication of it. My brother"s extensive correspondence with all those countries over which his philological studies extended brings upon me just at present, such a multiplicity of occupations and duties that I can only write you these few lines, my dear friend, as a pledge of my constant affection, and, I may also add, my admiration of your eminent works. It is a pleasure to watch the growing renown of those who are dear to us; and who should merit success more than you, whose elevation of character is proof against the temptations of literary self-love? I thank you for the little you have told me of your home life. It is not enough to be praised and recognized as a great and profound naturalist; to this one must add domestic happiness as well. . .