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Leaping the hedges with a butterfly amoeba

At the Milwaukee Public Museum with the butterflies.

I recently went to the Milwaukee Public Museum with my family.  This destination was carefully chosen because they have a butterfly exhibit, and my 5-year old daughter has developed a butterfly obsession.  In my experience, obsession of this sort is a good thing; in fact, it is the kind of thing that got me into science in the first place.  After I proudly watched her carefully hold and observe the different species of butterflies, and even have a few pleasant conversations with them, I wandered the exhibit and observed the diversity of colors and shapes myself.  There were some really spectacular species.

A butterfly amoeba

Perhaps because I recently had reason to open up Joseph Leidy’s incredibly beautiful 1879 foundational work describing North American testate amoebae (a group of amoebae that construct and live inside tests, or shells), my mind drifted to a statement Leidy made comparing a particular species of testate amoeba to a butterfly.  Apparently the simple beauty and elegance of this particular testate amoeba caused him to radically change his research focus.  He became obsessive about testate amoebae, or rhizopods as he called them. As with his previous research activities (e.g., paleontology, parisitology), his contributions to this new research area were enormous.

The testate amoeba in question was Hyalosphenia papilio.  In Leidy’s words:

“No other lobose rhizopod has more impressed me with its beauty than this one.  From its delicacy and transparency, its bright colors and form, as it moves among the leaves of sphagnum, desmids, and diatoms, I have associated it with the idea of a butterfly hovering among flowers.

A portion of a plate from Joseph Leidy’s 1879 monograph showing some of his drawings of Hyalosphenia papilio….the butterfly amoeba.

Leidy notes that he first observed the species thirty years prior to the publication of his seminal work, and seeing the species brought him fond memories of his explorations in the New Jersey pine barrens:

“Upward of thirty years ago, while examining the structure of sphagnum, my attention was distracted by the movements of a singular animal, whose character and affinities I did not then recognize.”

“This interesting Rhizopod, together with a profusion of other remarkable microscopic forms of both animal and vegetal life, of which many are novel and yet undescribed, recalls pleasing recollections of excursions into the sphagnous bogs, cedar swamps, and pine barrens in the southern region of New Jersey.

His fondness for the species is particularly evident in the next quote.  I can’t help to laugh a bit at the image of  him breaking out the microscope at a holiday dinner party, in order to display his “pets” to his friends.  Perhaps I should try this the next time I host a lab get together!

“I have collected it from early spring to late autumn, and have retained it alive in sphagnum, in a glass case, through the winter.  During the Christmas holidays, I have repeatedly exhibited it, in the living condition, to the admiration of friends.

A portion of a plate from Leidy’s 1865 Cretaceous Reptiles of the United States, showing some vertebrae from Hadrosaurus. (Image source)

What I find most interesting about this, is that Leidy was 50 years old when he decided to pursue this new line research.  He apparently dropped all of his other research endeavors, and focused solely on investigating these simple organisms for four or five years.  This shift in research focus was made by an already famous man who described the first complete dinosaur fossil, as well as many other North American fossils, and was widely recognized as the leading expert in parasitology.

A drawing of Trichina spiralis (now Trichinella spiralis), the  nematode parasite responsible for the disease trichinosis, done in 1887 by Joseph Leidy. Leidy first discovered that trichinosis was caused by a parasite that survived in undercooked meat (Chapman, 1891).  Image source: Collection 532. Joseph Leidy Teaching Diagrams. Academy of Natural Sciences of Philadelphia.

His obituary in the Proceedings of the National Academy of Arts and Sciences suggests that he left his paleontological research because of the extreme rivalries and unfriendly arguments that were shaping the field at the time – rather than get involved in these controversies Leidy may have just moved on.  He certainly would not be the only scientist to do such a thing.  However, according to his own words, it was the beauty of Hyalosphenia papilio that led him to study testate amoebae:

 “September 9th, 1873, the fiftieth anniversary of my birth, a friend, Clarence S. Bement, presented me with a Hartnack microscope, which, from its convenient size and form, I kept on my study table.  From time to time I was led to make observations on Fresh-water Rhizopods detected in sediments collected in the vicinity of Philadelphia.  A year later, in examining water squeezed from sphagnum obtained at Absecom, I observed many individuals of the same singular animal above indicated, but now, understanding its nature, I described it as Difflugia (Hyalosphenia) papilio.  It was the rediscovery of this beautiful form which impelled me to pursue the investigations which constitute the material of the present work.”

Published in 1897, his “Freshwater Rhizopods of North America” is a stunning combination of science and art, and still the most exhaustive description of North American testate amoebae.  For an interesting read on Leidy and the culture of science in mid-1800s North America, pick up a copy of Leonard Warren’s “Joseph Leidy: The last man who knew everything.”  For more on Leidy and a wonderful online version of the drawings included in the 1879 masterpiece, go here and here.

Joseph Leidy with his microscope circa 1870.

Leaping the hedges

The idea of following one’s interests, wherever they take you, is very attractive to me.  Of course, the culture of science has changed dramatically since the 1800s and scientists are generally narrower in focus and constrained by institutional expectations of tenure and promotion.  However, Leidy’s path of scientific exploration still seems a natural one, and I suspect that if more scientists followed his model instead of obsessively chasing promotion or the next big grant, we would collectively learn more about the natural world.

When I interviewed for a faculty position one of the questions that I was asked was to describe my 5-year research plan.  I was prepared for such a question, as it seemed like the sort of thing that I would be asked.  In fact, I carefully designed my research talk (candidates in academia usually “interview” for several days, typically giving one or two public lectures) to incorporate aspects of my long-term research plan.  Seven years later, perhaps not surprisingly, the most interesting science that I have done had little to do with my “plan.”  The projects that have excited me the most have been the things that I or my students have stumbled upon…things that I never could have planned.

I sincerely doubt that Joesph Leidy had a plan.  Sometimes something as simple as a beautiful amoeba, or a colorful butterfly, or perhaps an amoeba reminiscent of a butterfly…. can lead a scientist to wonderful new places.  Hopefully they will lead a certain 5-year old girl to some interesting places too.  The trick is identifying and following your passions (and obsessions), and knowing when it is time to move on to something new.  Leidy knew both…and he said so in the concluding statements of his great work:

“”I may perhaps continue in the same field of research and give to the reader further results, but I cannot promise to do so; for though the subject has proved to me an unceasing source of pleasure, I see before me so many wonderful things in other fields that a strong impulse disposes me to leap the hedges to examine them.””



After posting I ran into this great piece.  A nice example of testate amoebae as inspiration for art.

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