Book Excerpt from Louis Agassiz: Creator of American Science

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.