HOUGHTON MIFFLIN HARCOURT, FEBRUARY 2013Louis Agassiz’s world, in which each living thing occupies its assigned place in a taxonomic system and each scale tells us all we need to know about the fish to which it belongs, may seem static to some, frozen in predictability. But as we have seen in the last two chapters, e pur si muove: it moves nevertheless. In his mind, glaciers shifted and descended, fossils floated, jellyfish undulated, and fish frolicked in rivers too deep ever to be exhausted by fishermen. If rocks defined one pole of his imagination, water was the other one. Louis Agassiz was a marine biologist long before he had beheld an ocean.
And now, for the first time, settling down in his house on Webster Street in East Boston in the spring of 1847, he was living next to one. Agassiz was barely able to contain his excitement...
Agassiz, never one to stimulate the public’s interest without trying to take charge of it, had focused on animals that no one would be able to keep in an aquarium. From the fossil fish that had preoccupied him during his years in Neuchâtel, creatures cast in stone, Agassiz moved on to organisms that seemed to consist of nothing but water — jellyfish or medusae (as free-swimming jellyfish are also called), extremely fragile marine organisms that did not survive in captivity. On May 8 and 29, 1849, almost three years after his arrival in Boston, Agassiz, his English now less halting than it had been when he first set foot on the American shore, addressed the American Academy of Arts and Sciences about several new species of naked-eyed medusa —hydromedusae, in modern parlance —he had discovered. The written form of his remarks was published in 1850 in Memoirs of the American Academy of Arts and Sciences. Asserting with a flourish, on the very first page of the article that there was “a deep scientific interest connected with the study of Medusae,” Agassiz admitted that, since his arrival in Boston, his eyes had “hardly yet fully opened.” Seeing, observing, watching: for Agassiz, the New World was one giant invitation to take a closer look. And with jellyfish, perhaps more so than with other creatures, the right kind of seeing makes all the difference. The members of the genus Sarsia, for example, don’t exactly make things easy for the human observer. Fragile, transparent, unpredictable wisps of twitching, perishable matter, they refuse to sit still for their portraits. Transferring captured Sarsia swimming in a spoonful of seawater into a larger tumbler filled with more seawater will kill it instantly, as much as one tries to preserve the creature’s original environment. All the more remarkable, then, that Agassiz had used, as he reminded his readers, living animals for his descriptions whenever possible.
Throughout his article, Agassiz insists that when it came to choosing his specimens, he never cut corners. Never once did he simply place his objects of study instantly under the microscope where they would dry out. Instead, he looked at them while they were still alive, in narrow glass jars, surrounded by plenty of water. To him these jellyfish resembled beautiful flowers, and he gave them the care beautiful flowers deserved. Describing them was an education of the mind as well as the senses: the naked eye of the human observer adapts itself to the motions of the naked-eyed medusae. Here, indeed, we “learn . . . to look.”
Agassiz held that scientific observers share a fatal propensity to “force their views upon nature.” Not so Agassiz, who would wait for darkness to settle and then place a candle behind his jellyfish jar, gazing at his specimen with rapt attention because now “nothing about them can escape the attention of the observer,” especially one of Agassiz’s caliber. Amid a profusion of detail — a medusa’s epithelium, chymiferous tubes, pennate muscular bundles, and nerve plexuses — Agassiz, the questioning, puzzled, exhilarated investigator, remains always present, hungry for more. He makes no attempt to hide his excitement when he describes himself watching little Sarsia, freed from its earlier existence as polyp on a stem at the bottom of Boston Harbor, move forward by alternately contracting and extending its tiny body, its tentacles five times longer than the animal’s diameter: “Of course, the changes of form which it assumes in these different movements are almost endless; and though several are represented in Plate IV., they hardly give a complete idea of the beautiful diversity of aspect which this animal exhibits in its movements.” He reminds his readers that the evidence he has gathered is not always conclusive, that there is always a frustrating need for more work: “I must confess that I never met with more perplexing difficulties than those I experienced in satisfying myself of the real nature of what so clearly seemed a structure, which always vanished under certain influences of light, while it was so plain under others.” But Agassiz also takes care to communicate to his readers that what might seem discouraging at times is really quite exciting as well as aesthetically satisfying:
It is indeed a wonderful sight, to see a little animal not larger than a hazel-nut, as transparent as crystal, as soft as jelly, as perishable as an air-bubble, run actively through as dense a medium as water, pause at times and stretch its tentacles, and now dart suddenly in one direction or another, turn round upon itself, and move suddenly in the opposite direction, describe spirals like a bird of prey rising in the air, or shoot in a straight line like an arrow, and perform all these movements with as much grace and precision, and elongate and contract its tentacles, throw them at its prey, and secure, in that way, its food, with as much certainty, as could a larger animal provided with flesh and bones, teeth and claws, and all the different soft and hard parts which we consider generally as indispensable requisites for energetic action; though these little creatures are, strictly speaking, nothing more than a little mass of cellular gelatinous tissue.
Reprinted from Louis Agassiz: Creator of American Science, by Christoph Irmscher. Copyright © 2013 by Christoph Irmscher. Reproduced with permission from Houghton Mifflin Harcourt.