From what I have seen of the deep-sea bottom, I am already led to infer that among the rocks forming the bulk of the stratified crust of our globe, from the oldest to the youngest formation, there are probably none which have been formed in very deep waters. If this be so, we shall have to admit that the areas now respectively occupied by our continents, as circumscribed by the two hundred fathom curve or thereabout, and the oceans at greater depth, have from the beginning retained their relative outline and position; the continents having at all times been areas of gradual upheaval with comparatively slight oscillations of rise and subsidence, and the oceans at all times areas of gradual depression with equally slight oscillations. Now that the geological constitution of our continent is satisfactorily known over the greatest part of its extent, it seems to me to afford the strongest evidence that this has been the case; while there is no support whatever for the assumption that any part of it has sunk again to any very great depth after its rise above the surface of the ocean. The fact that upon the American continent, east of the Rocky Mountains, the geological formations crop out in their regular succession, from the oldest azoic and primordial deposits to the cretaceous formation, without the slightest indication of a great subsequent subsidence, seems to me the most complete and direct demonstration of my proposition. Of the western part of the continent I am not prepared to speak with the same confidence. Moreover, the position of the cretaceous and tertiary formations along the low grounds east of the Allegheny range is another indication of the permanence of the ocean trough, on the margin of which these more recent beds have been formed. I am well aware that in a comparatively recent period, portions of Canada and the United States, which now stand six or seven hundred feet above the level of the sea, have been under water; but this has not changed the configuration of the continent, if we admit that the latter is in reality circumscribed by the two hundred fathom curve of depth.
The summer was passed in his beloved laboratory at Nahant (as it proved, the last he ever spent there), where he was still continuing the preparation of his work on sharks and skates. At the close of the summer, he interrupted this occupation for one to which he brought not only the reverence of a disciple, but a life-long debt of personal gratitude and affection. He had been entreated to deliver the address at the Humboldt Centennial Celebration (September 15, 1869), organized under the auspices of the Boston Society of Natural History. He had accepted the invitation with many misgivings, for to literary work as such he was unaccustomed, and in the field of the biographer he felt himself a novice. His preparation for the task was conscientious and laborious. For weeks he shut himself up in a room of the Public Library in Boston and reviewed all the works of the great master, living, as it were, in his presence. The result was a very concise and yet full memoir, a strong and vigorous sketch of Humboldt's researches, and of their influence not only upon higher education at the present day, but on our most elementary instruction, until the very "school-boy is familiar with his methods, yet does not know that Humboldt is his teacher." Agassiz's picture of this generous intellect, fertilizing whatever it touched, was made the more life-like by the side lights which his affection for Humboldt and his personal intercourse with him in the past enabled him to throw upon it. Emerson, who was present, said of this address, "that Agassiz had never delivered a discourse more wise, more happy, or of more varied power." George William Curtis writes of it: "Your discourse seems to me the very ideal of such an address, —so broad, so simple, so comprehensive, so glowing, so profoundly appreciative, telling the story of Humboldt's life and work as I am sure no other living man can tell it." In memory of this occasion the "Humboldt Scholarship" was founded at the Museum of Comparative Zoology.
It is hardly worth while to consider now whether this effort, added to the pressing work of the year, hastened the attack which occurred soon after, with its warning to Agassiz that his overtasked brain could bear no farther strain. The first seizure, of short duration, but affecting speech and motion while it lasted, was followed by others which became less and less acute until they finally disappeared. For months, however, he was shut up in his room, absolutely withdrawn from every intellectual effort, and forbidden by his physicians even to think. The fight with his own brain was his greatest difficulty, and perhaps he showed as much power in compelling his active intellect to stultify itself in absolute inactivity for the time, as he had ever shown in giving it free rein. Yet he could not always banish the Museum, the passionate dream of his American life. One day, after dictating some necessary directions concerning it, he exclaimed, with a sort of despairing cry, "Oh, my Museum! my Museum! always uppermost, by day and by night, in health and in sickness, always—ALWAYS!"
He was destined, however, to a few more years of activity, the reward, perhaps, of his patient and persistent struggle for recovery. After a winter of absolute seclusion, passed in his sick chamber, he was allowed by his physician, in the spring of 1870, to seek change at the quiet village of Deerfield on the Connecticut River. Nature proved the best physician. Unable when he arrived to take more than a few steps without vertigo, he could, before many weeks were over, walk several miles a day. Keen as an Egyptologist for the hieroglyphics of his science, he was soon deciphering the local inscriptions of the glacial period, tracking the course of the ice on slab and dike and river-bed,—on every natural surface. The old music sang again in his ear and wooed him back to life.
In the mean time, his assistants and students were doing all in their power to keep the work of the Museum at high-water mark. The publications, the classification and arrangement of the more recent collections, the distribution of such portions as were intended for the public, the system of exchanges, went on uninterruptedly. The working force at the Museum was, indeed, now very strong. In great degree it was, so to speak, home-bred. Agassiz had gradually gathered about him, chiefly from among his more special students, a staff of assistants who were familiar with his plans and shared his enthusiasm. To these young friends he was warmly attached. It would be impossible to name them all, but the knot of younger men who were for years his daily associates in scientific work, whose sympathy and cooperation he so much valued, and who are now in their turn growing old in the service of science, will read the roll-call between the lines, and know that none are forgotten here. Years before his own death, he had the pleasure of seeing several of them called to important scientific positions, and it was a cogent evidence to him of the educational efficiency of the Museum, that it had supplied to the country so many trained investigators and teachers. Through them he himself teaches still. There was a prophecy in Lowell's memorial lines:—
"He was a Teacher: why be grieved for him
Whose living word still stimulates the air?
In endless file shall loving scholars come,
The glow of his transmitted touch to share."
Beside these, there were several older, experienced naturalists, who were permanently or transiently engaged at the Museum. Some were heads of departments, while others lent assistance occasionally in special work. Again the list is too long for enumeration, but as the veteran among the older men Mr. J.G. Anthony should be remembered. Already a conchologist of forty years' standing when he came to the Museum in 1863, he devoted himself to the institution until the day of his death, twenty years later. Among those who came to give occasional help were Mr. Lesquereux, the head of paleontological botany in this country; M. Jules Marcou, the geologist; and M. de Pourtales, under whose care the collection of corals was constantly improved and enlarged. The last named became at last wholly attached to the Museum, sharing its administration with Alexander Agassiz after his father's death.
To this band of workers some accessions had recently been made. More than two years before, Agassiz had been so fortunate as to secure the assistance of the entomologist, Dr. Hermann Hagen, from Konigsberg, Prussia. He came at first only for a limited time, but he remained, and still remains, at the Museum, becoming more and more identified with the institution, beside filling a place as professor in Harvard University. His scientific sympathy and support were of the greatest value to Agassiz during the rest of his life. A later new-corner, and a very important one at the Museum, was Dr. Franz Steindachner, of Vienna, who arrived in the spring of 1870 to put in final order the collection of Brazilian fishes, and passed two years in this country. Thus Agassiz's hands were doubly strengthened. Beside having the service of the salaried assistants and professors, the Museum received much gratuitous aid. Among the scientific volunteers were numbered for years Francois de Pourtales, Theodore Lyman, James M. Barnard, and Alexander Agassiz, while the business affairs of the institution were undertaken by Thomas G. Cary, Agassiz's brother-in-law. The latter had long been of great service to the Museum as collector on the Pacific coast, where he had made this work his recreation in the leisure hours of a merchant's life.* (* For the history of the Museum in later times reference is made to the regular reports and publications of the institution.)
Broken as he was in health, it is amazing to see the amount of work done or directed by Agassiz during this convalescent summer of 1870. The letters written by him in this time concerning the Museum alone would fill a good-sized volume. Such a correspondence is unfit for reproduction here, but its minuteness shows that almost the position of every specimen, and the daily, hourly work of every individual in the Museum, were known to him. The details of administration form, however, but a small part of the material of this correspondence. The consideration and discussion of the future of the Museum with those most nearly concerned, fill many of the letters. They give evidence of a fostering and far-reaching care, which provided for the growth and progress of the Museum, long after his own share in it should have ceased.
In reviewing Agassiz's scientific life in the United States, its brilliant successes, and the genial generous support which it received in this country, it is natural to give prominence to the brighter side. And yet it must not be forgotten that like all men whose ideals outrun the means of execution, he had moments of intense depression and discouragement. Some of his letters, written at this time to friends who controlled the financial policy of the Museum, are almost like a plea for life. While the trustees urge safe investments and the expenditure of income alone, he believes that in proportion to the growth and expansion of the Museum will be its power of self-maintenance and its claim on the community at large. In short, expenditure seemed to him the best investment, insuring a fair return, on the principle that the efficiency and usefulness of an institution will always be the measure of the support extended to it. The two or three following letters, in answer to letters from Agassiz which cannot be found, show how earnestly, in spite of physical depression, he strove to keep the Museum in relation with foreign institutions, to strengthen the former, and cooperate as far as possible with the latter.