Joseph Leidy and 'Fresh-water Rhizopods of North America'

(Above: a collage of a relevant portion of an 1879 map of the Wyoming Territories, part of Plate XXI of 'Rhizopods', and an image of a binocular version of Beck's 'Economic Microscope')

"Going fishing?" How often the question has been asked by acquaintances as they have met me, with rod and basket, on an excursion after materials for microscopic study. Yes! has been the invariable answer, for it saved much detention and explanation, and now, behold, I offer the results of that fishing. No fish for the stomach, but, as the old French microscopist Joblet observed, "some of the most remarkable fishes that have ever been seen"; and food fishes for the intellect."

Joseph Leidy and 'Fresh-water Rhizopods of North America'

There once was a man who knew everything. No really, I mean it. It is, amazingly, not a hyperbole. Joseph Leidy knew everything about Natural History there was to know in his time. He founded a great part of it, blazed the trails, mapped the country of it, and provided the foundation for many others who followed in his tracks. They then traveled down his paths, widened them, extended them, and, sadly, soon forgot their benefactor. His last great monograph, still referenced in the field, and still considered a masterpiece, is 'Fresh-water Rhizopods of North American', published in 1879 as Volume 12, of the 'Report of the United Stages Geological Survey of the Territories'. We'll try to dig a little into that great work and show how it might be useful to microscopists today. (Note: Hereafter I'll refer to this work as 'Rhizopods' because it's a heck of a lot shorter than the full title.)

First, though, because Leidy founded so many fields, and published so prodigiously (some 1500 papers and monographs!), even Warren's fairly recent biography on Leidy, which is 300 pages long, couldn't 'contain' the man as you would expect. So, I doubt I could cover him much here in these few pages. But you should spend some time exploring the 'Joseph Leidy Microscopy Portal', hereafter referred to as the JLMP, set up especially to support this article, which contains some excellent resources for you to savor. I think you will enjoy it.

Leidy as a microscopist

Leidy came on the scene before the microscope was really regarded as a serious research instrument—but he made it so. Warren, Leidy's biographer, notes that even as medical lecturers at the University of Pennsylvania openly doubted the usefulness of the microscope for any serious endeavor, let alone medical research, less than a block away, at the very instance, a young Leidy was actually doing just that. He rapidly became America's most famous microscopist. One day, just after the Civil War, his tax bill came from the IRS (The U.S. Internal Revenue Service). It read:

"Enclosed, please find your income tax bill; attend to it as soon as convenient in order to avoid the rush, Splendid weather for microscopy?" (Note: the italics are mine.)

Leidy used his microscopes constantly, applying them to any and all fields of interest—which were legion. Warren writes that late in life Leidy seemed addicted to buying microscopes (Oh dear, I hope this isn't a great sin), and he "spent hours with makers of microscopes, discussing their structure and care".

"By 1853, when Leidy's annotated American edition of Gluge's Atlas of Pathological Histology was published, he was a veteran microscopist, called upon by friends and strangers from all parts of the country for help in the purchase and repair of microscopes. Some even requested Leidy to buy microscopes for them on credit. He quietly did his best to accommodate everyone."

Leidy's microscopes

We do know the type of microscope that Leidy used for 'Rhizopods' - and as for its make and model it was most probably Beck's 'Economic Microscope'.

See JLMP for a link to a larger image (all courtesy of the Smithsonian Collections). The description for this scope, and image above, reveal that it had 1" and ¼" objectives, with two eyepieces, giving powers from 45x to 330x, and a mirror (concave) mounted on a swing-able bar to allow oblique lighting. Also of importance: it had a bulls-eye condensing lens mounted on the stage for reflected light use. Other objectives were available for this scope, offered separately, and it also came in a binocular version (as seen in the colored banner image at the top of this article, see also JLMP).

Leidy's main mode of using the scope would have been normal Bright Field (BF) but he notes in 'Rhizopods' that he also used reflected light (courtesy of the mounted stage lens?), and would certainly have made use of the oblique features of the configurable mirror. Dark Field (DF) is not mentioned, that I can see, but certainly Leidy would have been aware of the technique as it occurs often when adjusting the mirror (a finger between mirror and condenser is enough to give DF at low power, as many of us find out today).

Leidy's scope would have had to have been tough, able to be jostled and jolted at times, in a carriage, on a frontier train, packed on a mule into the 'high country', and set-up on a camp stool, rock, or tree trunk. His lighting options would have been oil lamp, when he could get it, and certainly, more times than he wanted, the sky above. I suppose many times he must have cursed the coming twilight, and cried 'My kingdom for a better light!' . . . but I don't want to leave the impression that Leidy sought high adventure—the opposite really.

Where Leidy collected his subjects of study

He preferred to collect his subjects locally, around Philadelphia, and he turned down a trip to the Amazon because he really did not see the need to go far abroad to find interesting, and unknown, things to describe—a good lesson for us all. The birdbath in your back yard may be, on a microscopic scale, as unexplored as the deepest trench in the vast ocean deep. But the neighbors may view you as a little eccentric for hovering around it so—just as one acquaintance remarked that Leidy was "absorbed in his new discoveries of rhizopods in the cracks of the city pavements".

For 'Rhizopods' though, Leidy was quite explicit about where he collected—see page 13 of 'The Introduction' on JLMP for all details—but mainly the ponds, marshes, and springs along the Delaware and Schuylkill Rivers in Pennsylvania and New Jersey, but also in Connecticut, Rhode Island, as far west as the Wyoming Territories, and even at the head of the Bay of Fundy, in Nova Scotia. Though, in the body of 'Rhizopods', Leidy sometimes gives interesting detail (e.g., collecting from a cow track in a swampy meadow).

A section of 'Rhizopods' entitled 'Lists of Fresh-Water Rhizopods ' gives 'species counts' for example collecting sites. For instance, one such site was in the slime, scraped off with a knife blade, from dripping rocks at a reservoir near Philadelphia. Click on the thumbnail below to see this page at full resolution.

These kinds of studies seem to be in reach of a dedicated amateur, and are done today, albeit with an eye to identifying populations against a measured variable (s) - depth of soil, season, etc. Examples: See here, or here (and not to be missed, here).

His Masterpiece: "Fresh-water Rhizopods of North America"

It seemed to almost kill him in the end— finishing up this monumental work, that is. He couldn't eat or sleep, it drove him so, as he worked it into final form. The 4 years of study, toil, collecting, and observing behind its pages had also been taxing. But the Wild West was tamed by that time . . . or was it? On the trip to Wyoming they passed horse thieves hanged on telephone poles along the track, saw Indians on horseback gawking at the 'iron horse', and battled hordes of bedbugs in an Omaha Hotel, to end up defeated, and beating a hasty retreat to spend the night in a saloon reeking of liquor and tobacco smoke. In the high Uinta mountains of Utah and Wyoming, far from relative comfort at Fort Bridger, Leidy and his companions, fought hordes of mosquitoes, toiled all day long in the hot sun, and slept in buffalo robes in the freezing mountain air, all the while collecting and observing for weeks on end.

(Above: The 48 color plates as tiny thumbnails in a collage, alongside a full resolution scan of A. Proteus from Plate # 1. Sorry about the little guy fleeing the Amoeba, I guess I just watched too many re-runs of the horror movie 'The Blob' for my own good as a kid)

These plates, and their keys, makeup, in 'bulk', the last half of the book (the color plates are printed on extra heavy paper). An Index in front of the 48 plates links each organism (sometimes spread across more than one plate) to the body of the preceding text.

For instance: Plate XVII (i.e. 17 - Roman Numerals are not my forte either) is filled with images of Difflugia Corona. The index shows that Difflugia Corona (noted as D. Corona) is discussed on pages 117 and 118 of the text. Pages 117 and 118 of the text, do, in fact, discuss D. Corona, and the text of these pages refers continually back to Plate XVII. The 'Key' for the plate discusses each figure, gives size, magnification, collection details, morphology, etc.

Note: Full resolution scans of the color plates and keys are available at the JLMP.

The images from the color plates give a person a perspective and sense of shape and depth that only careful observation and drawing can produce. Yes, today, we can use optical sectioning and image stitching, provided the subject cooperates and remains very still (Don't move now. P l e a s e stop moving those pseudopods! Argghh!).

Bottom line: Leidy spent long and careful hours observing to build up such '3-D' images as are found on the Plates.

The body of the text, however, is a true treasure trove for the Amoeba lover. As an example, Hyalosphenia Papilo, a subject Leidy loved, can be found in standard references like:

But Leidy provides a lot more information on this organism— really 8 pretty dense pages and many color images—click on the thumbnails to see:

p. 131	p.132	p. 133	p. 134	p. 135
p. 136	p. 137	p. 138	Plate 21	'Key' to Plate 21

Remember how when you were a kid that when someone your age moved into your neighbor hood and you had them over to play, that your Dad wanted to know what their name was, and what-their-dad did for a living, etc; while you, on the other hand, wanted to find out if they liked the color 'Blue', and what their favorite flavor of ice-cream was, and did they have a tree-house, and if not, would they like to help you build one, etc., etc. W e l l, that's like comparing Kudo and Jahn to Leidy. Yes, the name of the organism is important, as are the other things Kudo and Jahn report, but Leidy tells you these and all the things you really wanted to know about, and some you didn't know enough to ask about.

Nevertheless, Leidy admits that he couldn't tell all that was tell-able or knowable:

"In the study of Rhizopods, my attention has been more particularly directed to the discovery and determination of the various forms occurring in this country, rather than to the elaboration of details of structure, habits, modes of development, and other matters pertaining to their history, though these have not been entirely neglected."

He left this 'telling' to those that followed, and -you- are surely one of them. To that point . . .

What can you learn from the 127 year-old observations of a pioneering microscopist?

You've asked yourself this question haven't you? W e l l . . . in Leidy, you have:

(3) With fewer techniques at his disposal than you have (Leidy had no phase, no ultra-deep DF, no DIC, no photomicrography, no image stacking software, or capture software, etc, etc.)

Who has shown you, through expert drawings, and at-length descriptions, exactly what he saw when looking at subjects that are easily within your grasp.

Can you match his observations? Can you see what he saw, let alone see more? Can you answer the questions he asks, now that you are standing atop 127 years of progress?

By using Leidy as a guide in your explorations, matching your observations to his, you can train yourself to patiently observe, missing nothing. Once you meet that standard, you can then apply those keen observing skills to areas into which Leidy never ventured.

"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."