I wish I could accept your kind invitation, but until I have gone to the bottom of the glacier question and terminated my "Fossil Fishes," I do not venture to move. It is no light task to finish all this before our long journey, to which I look forward, as it draws nearer, with a constantly increasing interest. I am very sorry not to join you at Florence. It would have been a great pleasure for me to visit the collections of northern Italy in your company. . .I write you on a snowy day, which keeps me a prisoner in my tent; it is so cold that I can hardly hold my pen, and the water froze at my bedside last night. The greatest privation is, however, the lack of fruit and vegetables. Hardly a potato once a fortnight, but always and every day, morning and night, mutton, everlasting mutton, and rice soup. As early as the end of July we were caught for three days by the snow; I fear I shall be forced to break up our encampment next week without having finished my work.
What a contrast between this life and that of the plain! I am afraid my letter may be long on the road before reaching the mail, and I pause here that I may not miss the chance of forwarding it by a man who has just arrived with provisions and is about to return to the hospice of the Grimsel, where some trustworthy guide will undertake to deliver it at the first post-office.
No sooner is Aga.s.siz returned from the glacier than we meet him again in the domain of his fossil fishes.
LOUIS AGa.s.sIZ TO SIR PHILIP EGERTON.
NEUCHATEL, December 15, 1842.
. . .In the last few months I have made an important step in the identification of fossil fishes. The happy idea occurred to me of applying the microscope to the study of fragments of their bones, especially those of the head, and I have found in their structure modifications as remarkable and as numerous as those which Mr. Owen discovered in the structure of teeth. Here there is a vast new field to explore. I have already applied it to the identification of the fossil fishes in the Old Red of Russia sent me for that purpose by Mr. Murchison. You will find more ample details about it in my report to him. I congratulate myself doubly on the results; first, because of their great importance in paleontology, and also because they will draw more closely my relations with Mr. Owen, whom I always rejoice to meet on the same path with myself, and whom I believe incapable of jealousy in such matters. . .The only point indeed, on which I think I may have a little friendly difference with him, is concerning the genus Labyrinthodon, which I am firmly resolved, on proofs that seem to me conclusive, to claim for the cla.s.s of fishes.* (* On seeing Owen"s evidence some years later, Aga.s.siz at once acknowledged himself mistaken on this point.
) As soon as I have time I will write to Mr. Owen, but this need not prevent you from speaking to him on the subject if you have an early opportunity to do so. I am now exclusively occupied with the fossil fishes, which at any cost I wish to finish this winter. . .
Before even returning to my glacier work, I will finish my monograph of the Old Red, so that you may present it at the Cork meeting, which it will be impossible for me to attend. . .I am infinitely grateful to you and Lord Enniskillen for your willingness to trust your Sheppy fishes to me; I shall thus be prepared in advance for a strict determination of these fossils.
Having them for some time before my eyes, I shall become familiar with all the details. When I know them thoroughly, and have compared them with the collections of skeletons in the Museums of Paris, of Leyden, of Berlin, and of Halle, I will then come to England to see what there may be in other collections which I cannot have at my disposal here.
The winter of 1843, apart from his duties as professor, was devoted to the completion of the various zoological works on which he was engaged, and to the revision of materials he had brought back from the glacier. His habits with reference to physical exercise were very irregular. He pa.s.sed at once from the life of the mountaineer to that of the closet student. After weeks spent on the snow and ice of the glacier, constantly on foot and in the open air, he would shut himself up for a still longer time in his laboratory, motionless for hours at his microscope by day, and writing far into the night, rarely leaving his work till long after midnight. He was also forced at this time to press forward his publications in the hope that he might have some return for the sums he had expended upon them. This was indeed a very anxious period of his life. He could never be brought to believe that purely intellectual aims were not also financially sound, and his lithographic establishment, his glacier work, and his costly researches in zoology had proved far beyond his means. The prophecies of his old friend Humboldt were coming true. He was entangled in obligations, and crushed under the weight of his own undertakings. He began to doubt the possibility of carrying out his plan of a scientific journey to the United States.
AGa.s.sIZ TO THE PRINCE OF CANINO.
NEUCHATEL, April, 1843.
. . .I have worked like a slave all winter to finish my fossil fishes; you will presently receive my fifteenth and sixteenth numbers, forwarded two days since, with more than forty pages of text, containing many new observations. I shall allow myself no interruption until this work is finished, hoping thereby to obtain a little freedom, for if my position here is not changed I shall be forced to seek the means of existence elsewhere. Meantime, extravagant projects present themselves, as is apt to be the case when one is in difficulties. That of accompanying you to the United States was so tempting, that I am bitterly disappointed to think that its execution becomes impossible in my present circ.u.mstances.
All my projects for further publications must also be adjourned, or perhaps renounced. . .Possibly, when my work on the fossil fishes is completed, the sale of some additional copies may help me to rise again. And yet I have not much hope of this, since all the attempts of my friends to obtain subscriptions for me in France and Russia have failed: because the French government takes no interest in what is done out of Paris; and in Russia such researches, having little direct utility, are looked upon with indifference. Do you think any position would be open to me in the United States, where I might earn enough to enable me to continue the publication of my unhappy books; which never pay their way because they do not meet the wants of the world?. . .
In the following July we find him again upon the glacier. But the campaign of 1843 opened sadly for the glacial party. Arriving at Meiringen they heard that Jacob Leuthold was ill and would probably be unable to accompany them. They went to his house, and found him, indeed, the ghost of his former self, apparently in a rapid decline. Nevertheless, he welcomed them gladly to his humble home, and would have kept them for some refreshment. Fearing to fatigue him, however, they stayed but a few moments. As they left, one of the party pointed to the mountains, adding a hope that he might soon join them. His eyes filled with tears; it was his only answer, and he died three days later. He was but thirty-seven years of age, and at that time the most intrepid and the most intelligent of the Oberland guides. His death was felt as a personal grief by the band of workers whose steps he had for years guided over the most difficult Alpine pa.s.ses.
The summer"s work continued and completed that of the last season.
On leaving the glacier the year before they had marked a network of loose boulders, such as travel with the ice, and also a number of fixed points in the valley walls, comparing and registering their distance from each other. They had also sunk a line of stakes across the glacier. The change in the relative position of the two sets of signals and the curve in their line of stakes gave them, self-recorded, as it were, the rate of advance of the glacier as a whole, and also the comparative rate of progression in its different parts. Great pains was also taken during the summer to measure the advance in every twenty-four hours, as well as to compare the diurnal with the nocturnal movement, and to ascertain the amount of surface waste. The season was an unfavorable one, beginning so late and continuing so cold that the period of work was shortened.
CHAPTER 12.
1843-1846: AGE 36-39.
Completion of Fossil Fishes.
Followed by Fossil Fishes of the Old Red Sandstone.
Review of the Later Work.
Identification of Fishes by the Skull.
Renewed Correspondence with Prince Canino about Journey to the United States.
Change of Plan owing to the Interest of the King of Prussia in the Expedition.
Correspondence between Professor Sedgwick and Aga.s.siz on Development Theory.
Final Scientific Work in Neuchatel and Paris.
Publication of "Systeme Glaciaire."
Short Stay in England.
Farewell Letter from Humboldt.
Sails for United States.
In 1843 the "Recherches sur les Poissons Fossiles" was completed, and fast upon its footsteps, in 1844, followed the author"s "Monograph on the Fossil Fishes of the Old Red Sandstone, or the Devonian System of Great Britain and Russia," a large quarto volume of text, accompanied by forty-one plates. Nothing in his paleontological studies ever interested Aga.s.siz more than this curious fauna of the Old Red, so strange in its combinations that even well-informed naturalists had attributed its fossil remains to various cla.s.ses of the animal kingdom in turn, and, indeed, long remained in doubt as to their true nature. Aga.s.siz says himself in his Preface: "I can never forget the impression produced upon me by the sight of these creatures, furnished with appendages resembling wings, yet belonging, as I had satisfied myself, to the cla.s.s of fishes. Here was a type entirely new to us, about to reenter (for the first time since it had ceased to exist) the series of beings; nor could anything, thus far revealed from extinct creations, have led us to antic.i.p.ate its existence. So true is it that observation alone is a safe guide to the laws of development of organized beings, and that we must be on our guard against all those systems of transformation of species so lightly invented by the imagination."
The author goes on to state that the discovery of these fossils was mainly due to Hugh Miller, and that his own work had been confined to the identification of their character and the determination of their relations to the already known fossil fishes. This work, upon a type so extraordinary, implied, however, innumerable and reiterated comparisons, and a minute study of the least fragments of the remains which could be procured. The materials were chiefly obtained in Scotland; but Sir Roderick Murchison also contributed his own collection from the Old Red of Russia, and various other specimens from the same locality. Not only on account of their peculiar structure were the fishes of the Old Red interesting to Aga.s.siz, but also because, with this fauna, the vertebrate type took its place for the first time in what were then supposed to be the most ancient fossiliferous beds. When Aga.s.siz first began his researches on fossil fishes, no vertebrate form had been discovered below the coal. The occurrence of fishes in the Devonian and Silurian beds threw the vertebrate type back, as he believed, into line with all the invertebrate cla.s.ses, and seemed to him to show that the four great types of the animal kingdom, Radiates, Mollusks, Articulates, and Vertebrates, had appeared together.* (*
Introduction to the "Poissons Fossiles de Vieux Gres Rouge" page 22.) "It is henceforth demonstrated," says Aga.s.siz, "that the fishes were included in the plan of the first organic combinations which made the point of departure for all the living inhabitants of our globe in the series of time."
In his opinion this simultaneity of appearance, as well as the richness and variety displayed by invertebrate cla.s.ses from the beginning, made it* (* Introduction to the "Poissons Fossiles du Vieux Gres Rouge" page 21.) "impossible to refer the first inhabitants of the earth to a few stocks, subsequently differentiated under the influence of external conditions of existence.". . .He adds:* (* Introduction to the "Poissons Fossiles de Vieux Gres Rouge" page 24.) "I have elsewhere presented my views upon the development through which the successive creations have pa.s.sed during the history of our planet. But what I wish to prove here, by a careful discussion of the facts reported in the following pages, is the truth of the law now so clearly demonstrated in the series of vertebrates, that the successive creations have undergone phases of development a.n.a.logous to those of the embryo in its growth and similar to the gradations shown by the present creation in the ascending series, which it presents as a whole. One may consider it as henceforth proved that the embryo of the fish during its development, the cla.s.s of fishes as it at present exists in its numerous families, and the type of fish in its planetary history, exhibit a.n.a.logous phases through which one may follow the same creative thought like a guiding thread in the study of the connection between organized beings." Following this comparison closely, he shows how the early embryonic condition of the present fishes is recalled by the general disposition of the fins in the fishes of the Old Red Sandstone, and especially by the caudal fin, making the unevenly lobed tail, so characteristic of these ancient forms. This so called heterocercal tail is only known to exist, as a permanent adult feature, in the sturgeons of to-day.
The form of the head and the position of the mouth and eyes in the fishes of the Old Red were also shown to be a.n.a.logous with embryonic phases of our present fishes. From these a.n.a.logies, and also from the ascendancy of fishes as the only known vertebrate, and therefore as the highest type in those ancient deposits, Aga.s.siz considered this fauna as representing "the embryonic age of the reign of fishes;" and he sums up his results in conclusion in the following words: "The facts, taken as a whole, seem to me to show, not only that the fishes of the Old Red const.i.tute an independent fauna, distinct from those of other deposits, but that they also represent in their organization the most remarkable a.n.a.logy with the first phases of embryonic development in the bony fishes of our epoch, and a no less marked parallelism with the lower degrees of certain types of the cla.s.s as it now exists on the surface of the earth."
It has been said by one of the biographers of Aga.s.siz,* (* "Louis Aga.s.siz: Notice biographique" par Ernest Favre.) in reference to this work upon the fishes of the Old Red Sandstone: "It is difficult to understand why the results of these admirable researches, and of later ones made by him, did not in themselves lead him to support the theory of transformation, of which they seem the natural consequence." It is true that except for the frequent allusion to a creative thought or plan, this introduction to the Fishes of the Old Red might seem to be written by an advocate of the development theory rather than by its most determined opponent, so much does it deal with laws of the organic world, now used in support of evolution. These comprehensive laws, announced by Aga.s.siz in his "Poissons Fossiles," and afterward constantly reiterated by him, have indeed been adopted by the writers on evolution, though with a wholly different interpretation. No one saw more clearly than Aga.s.siz the relation which he first pointed out, between the succession of animals of the same type in time and the phases of their embryonic growth to-day, and he often said, in his lectures, "the history of the individual is the history of the type." But the coincidence between the geological succession, the embryonic development, the zoological gradation, and the geographical distribution of animals in the past and the present, rested, according to his belief, upon an intellectual coherence and not upon a material connection. So, also, the variability, as well as the constancy, of organized beings, at once so plastic and so inflexible, seemed to him controlled by something more than the mechanism of self-adjusting forces. In this conviction he remained unshaken all his life, although the development theory came up for discussion under so many various aspects during that time. His views are now in the descending scale; but to give them less than their real prominence here would be to deprive his scientific career of its true basis.
Belief in a Creator was the keynote of his study of nature.
In summing up the comprehensive results of Aga.s.siz"s paleontological researches, and especially of his "Fossil Fishes,"
Arnold Guyot says:* (* See "Biographical Memoir of Louis Aga.s.siz"
page 28.)--"Whatever be the opinions which many may entertain as to the interpretation of some of these generalizations, the vast importance of these results of Aga.s.siz"s studies may be appreciated by the incontestable fact, that nearly all the questions which modern paleontology has treated are here raised and in great measure solved. They already form a code of general laws which has become a foundation for the geological history of the life-system, and which the subsequent investigations of science have only modified and extended, not destroyed. Nowhere did the mind of Aga.s.siz show more power of generalization, more vigor, or more originality. The discovery of these great truths is truly his work; he derived them immediately from nature by his own observations.
Hence it is that all his later zoological investigations tend to a common aim, namely, to give by farther studies, equally conscientious but more extensive, a broader and more solid basis to those laws which he had read in nature and which he had proclaimed at that early date in his immortal work, "Poissons Fossiles." Let us not be astonished that he should have remained faithful to these views to the end of his life. It is because he had SEEN that he BELIEVED, and such a faith is not easily shaken by new hypotheses."
LOUIS AGa.s.sIZ TO SIR PHILIP EGERTON.
NEUCHATEL, September 7, 1844.
. . .I write in all haste to ask for any address to which I can safely forward my report on the Sheppy fishes, so that they may arrive without fail in time for the meeting at York. Since my last letter I have made progress in this kind of research. I have sacrificed all my duplicates of our present fishes to furnish skeletons. I have prepared more than a hundred since I last wrote you, and I can now determine the family, and even the genus, simply by seeing the skull. There remains nothing impossible now in the determination of fishes, and if I can obtain certain exotic genera, which I have not as yet, I can make an osteology of fishes as complete as that which we possess for the other cla.s.ses of vertebrates. Every family has its special type of skull. All this is extremely interesting. I have already corrected a ma.s.s of inaccurate identifications established upon external characters; and as for fossils, I have recognized and characterized seventeen new genera among the less perfect undetermined specimens you have sent me. Several families appear now for the first time among the fossils. I have been able to determine to what family all the doubtful genera belong; indeed Sheppy will prove as rich in species as Mont Bolca. When you see your specimens again you will hardly recognize them, they are so changed; I have chiseled and cleaned them, until they are almost like anatomical preparations. Try to procure as many more specimens as possible and send them to me. I cannot stir from Neuchatel, now that I am so fully in the spirit of work, and besides it would be a useless expense. . .You will receive with my report the three numbers which complete my monograph of the Fishes of the Old Red. I feel sure, in advance, that you will be satisfied with them. . .
SIR PHILIP EGERTON TO LOUIS AGa.s.sIZ.
TOLLY HOUSE, ALNESS, ROSS-SHIRE. September 15, 1844.
. . .I have only this day received your letter of the 6th, and I fear much you will scarcely receive this in time to make it available. I shall not be able to reach York for the commencement of the meeting, but hope to be there on Sat.u.r.day, September 28th. A parcel will reach me in the shortest possible time addressed Sir P.
Egerton, Donnington Rectory, York. I am delighted with the bright results of your comparison of the Sheppy fossils with recent forms.
You appear to have opened out an entirely new field of investigation, likely to be productive of most brilliant results.
Should any accident delay the arrival of your monograph for the York meeting, I shall make a point of communicating to our scientific friends the contents of your letter, as I know they will rejoice to hear of the progress of fossil ichthyology in your masterly hands. When next you come, I wish you could spend a few days here. We are surrounded on all sides by the debris of the moraines of the ancient glaciers that descended the flank of Ben Wyvis, and I think you would find much to interest you in tracing their relations. We have also the Cromarty Fish-beds within a few miles, and many other objects of geological interest. . .I shall see Lord Enniskillen at York, and will tell him of your success. We shall, of course, procure all the Sheppy fish we can either by purchase or exchange. . .
The pressure of work upon his various publications detained Aga.s.siz at home during the summer of 1844. For the first time he was unable to make one of the glacial party this year, but the work was carried on uninterruptedly, and the results reported to him.
Meantime his contemplated journey to the United States flitted constantly before him.
AGa.s.sIZ TO THE PRINCE OF CANINO.
NEUCHATEL, November 19, 1844.
. . .Your idea of an ill.u.s.trated American ichthyology is admirable.
But for that we ought to have with us an artist clever enough to paint fishes rapidly from the life. Work but half done is no longer permissible in our days. . .In this matter I think there is a justice due to Rafinesque. However poor his descriptions, he nevertheless first recognized the necessity of multiplying genera in ichthyology, and that at a time when the thing was far more difficult than now. Several of his genera have even the priority over those now accepted, and I think in the United States it would be easier than elsewhere to find again a part of the materials on which he worked. We must not neglect from this time forth to ask Americans to put us in the way of extending this work throughout North America. If you accept me for your collaborator, I will at once do all that I can on my side to bring together notes and specimens. I will write to several naturalists in the United States, and tell them that as I am to accompany you on your voyage I should be glad to know in advance what they have done in ichthyology, so that we may be the better prepared to profit by our short sojourn in their country. However, I will do nothing before having your directions, which, for the sake of the matter in hand, I should be glad to receive as early as possible. . .
The next letter announces a new aspect of the projected journey. In explanation, it should be said that finding Aga.s.siz might be prevented by his poverty from going, the prince had invited him to be his guest for a summer in the United States.
AGa.s.sIZ TO THE PRINCE OF CANINO.
NEUCHATEL, January 7, 1845.
. . .I have received an excellent piece of news from Humboldt, which I hasten to share with you. I venture to believe that it will please you also. . .I had written to Humboldt of our plans, and of your kind offer to take me with you to the United States, telling him at the same time how much I regretted that I should be unable to visit the regions which attracted me the most from a geological point of view, and asking him if it would be possible to interest the king in this journey and obtain means from his majesty for a longer stay on the other side of the Atlantic. I have just received a delightful and most unexpected reply. The king will grant me 15, 000 francs for this object, so that I shall, in any event, be able to make the journey. All the more do I desire to make it in your society, and I think by combining our forces we shall obtain more important results; but I am glad that I can do it without being a burden to you. Before answering Humboldt, I am anxious to know whether your plans are definitely decided upon for this summer, and whether this arrangement suits you. . .
The pleasant plan so long meditated was not to be fulfilled. The prince was obliged to defer the journey and never accomplished it.
This was a great disappointment to Aga.s.siz.
"Am I then to go without you," he writes; "is this irrevocable? If I were to defer my departure till September would it then be possible for you to leave Rome? It would be too delightful if we could make this journey together. I wish also, before starting, to review everything that has been done of late in paleontology, zoology, and comparative anatomy, that I may, in behalf of all these sciences, take advantage of the circ.u.mstances in which I shall be placed. . .Whatever befalls me, I feel that I shall never cease to consecrate my whole energy to the study of nature; its all powerful charm has taken such possession of me that I shall always sacrifice everything to it; even the things which men usually value most."
Aga.s.siz had determined, before starting on his journey, to complete all his unfinished works, and to put in order his correspondence and collections, including the vast amount of specimens sent him for identification or for his own researches. The task of "setting his house in order" for a change which, perhaps, he dimly felt to be more momentous than it seemed, proved long and laborious. From all accounts, he performed prodigies of work, but the winter and spring pa.s.sed, and the summer of 1845 found him still at his post.