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From “out of date junk” to “exciting and rare” – our microscope collection

At the moment, sorting out the cupboards before our move has become very exciting as I’ve reached the microscope collection. Much of it was stored in the 1950s when the Laboratory of Microbiology moved from its original building, and has rarely been disturbed since then. Some of the microscopes date from the late 19th century, and even some of the 20th century ones are more interesting than might be expected.

The youngest of the companies represented in our microscope collection is probably the least well-known, especially outside the Netherlands.

Bleeker Nedoptifa

Founded by Dr Caroline E. (Lili) Bleeker and Gerard Willemse in 1939, Nedoptifa rapidly became known for the high standard of their optical products. They began with the production of binoculars for the Dutch army, but production was interrupted by WW2. Most of their microscope production seems to have been after 1945, when the “Nedoptifa” name came into use. The company cooperated with the Nobel prize-winner, Frits Zernike, in the development of phase contrast microscopy and held his patent on phase contrast microscopes. Bleeker retired at the end of 1963, the company was eventually taken over by a Delft firm and then in 1978 the factory in Zeist was closed.

Kluyver’s group seems to have used the basic Nedoptifa microscope for teaching – we have quite a few of them. Most of them have the standard circular stage, but a few are square. We also have one of their very early binocular microscopes as well as monocular and binocular phase contrast microscopes. Most of them, with the exception of the binocular phase contrast microscope, seem to have been use in in the laboratory before 1955.

Note added later: Disappointingly, after a visit in mid-June from Peter Paul de Bruyn, an expert on Bleeker microscopes, it seems that the microscopes whose boxes proclaimed them to be phase contrast microscopes do not have the necessary lenses or fittings. They may appear as we complete the packing of the collection, but it’s beginning to look unlikely.

Carl Zeiss Jena

This famous old microscope manufacturer needs no introduction. In what is probably our most famous portrait of Prof Beijerinck, he is clearly using one of their “jug handled” microscopes. Others in our collection are in the Zeiss catalogues of the late 19th century.

We also have some more unusual examples of their work including a “horizontal microscope” (intended for examining living plants) and a binocular microscope fitted with a prism on the right ocular to aid the drawing of samples.

I really shouldn’t have favourites, but I must admit a fondness for the very heavy preparation microscope that turned up in a battered old wooden box on top of a cupboard. When it is taken out of the box, the eyepieces on the right flip up, giving a forerunner of our modern stereomicroscopes which can be found in the 1902 Carl Zeiss Catalogue. There are 2 sets of lenses and oculars. During dissections, the microscope can be moved backwards and forwards along the metal bar.

Early Zeiss preparation or dissecting microscope

Early Zeiss preparation or dissecting microscope

Ernst Leitz Wetzlar

Another famous old company, Leitz seems to have been a favourite with Professor van Iterson. Among the microscopes from this company are a “measuring microscope”, a preparation microscope with wrist supports and the microscope (with an extensive collection of extra attachments) that he used after he retired.

Other companies

Other microscope makers are mostly represented by single instruments, so I will only show two of the most spectacular. First is the interference microscope made by Cooke, Troughton & Simms from the Van Iterson collection. This microscope is accompanied by a set of extra attachments and filters.

And lastly, one of the most unusual microscopes in our collection, a reversed microscope made by Nachet & Fils of Paris. The sample lies on the stage and can be illuminated from above, with the observer’s light path underneath the stage. It appears in the 1898 Nachet catalogue. This microscope was given to the collection by Dr and Mrs ten Hoopen, both of whom worked in the Department of Applied Botany before volunteering to help with the Archive and Museum after they retired.

The Delft School of Microbiology Archive owes a huge debt to both of them. Truus undertook two major tasks. First she restored our enormous collection of glass negatives (see the blogpost “Glass negatives galore!”) after they all got damp during asbestos removal in the attic where they were stored. She then went on to research and catalogue our collections of original and printed botanic and microbiological wall charts (see blogposts “The art of Henriette Beijerinck” and “Educational Wall Charts – where are they now?”). Meanwhile, Hens catalogued the microscopes and other equipment (we have the most amazing range of pH meters, for example) in our collection.

Without Truus and Hens ten Hoopen, we would know a lot less about the Collection than we do.

Reversed light path microscope by Nachet et fils

Reversed light path microscope by Nachet et fils

Delft University’s Biological Labs 1: The “Palace of Light” on the Nieuwelaan.

At the beginning of 2016, the Laboratory for Microbiology, together with the rest of the Department of Biotechnology, will move out of its current building, destination the new Faulty building on the outskirts of Delft. This seems like a good moment to take a look at the previous lab where so many breakthroughs were made. It was known as the “Palace of Light” because people worked late into the night.

We are fortunate that, thanks to a commemorative book published when Beijerinck was a fairly new Professor and photographs taken just before the department moved out, we know what it looked like. At the time it was built, it was the most expensive laboratory in the University. An extension was added in 1911.

Beijerinck’s laboratory

Part of the building, on the left of the top photo, was the Professor’s house. The garden sloped gently down to a large canal (the canal’s edge can be seen as a white line across the bottom of the picture). It was in the greenhouse in this garden that the tobacco plants were grown for Beijerinck’s work on the Tobacco Mosaic Virus, and many famous microbial species were isolated from the soil and mud of the garden and canal.

We have a few pictures of the inside of the lab in Beijerinck’s time.

After Kluyver’s death and before everybody moved to the new (and current) building, everything was photographed. The photos are all numbered with corresponding floor plans so that we know not only which room is shown, but where the photographer was standing to take the picture. This is just a small sample.

The building (without the extension) is still there. After a number of trials and tribulations including the building of a major bridge close to the front door of Beijerinck and Kluyver’s house, it is now apartments. To mark the 100th anniversary of Beijerinck’s appointment, a plaque was unveiled next to the original laboratory door.

The art of Henriette Beijerinck

HWB
The laboratory was well supplied with printed botanic wall charts, but there was always a need for things that weren’t available. During Beijerinck’s professorship, his sister Henriette provided most of his display material, generally as large (A1 or A2 in modern terms) watercolours. Henriette Beijerinck was a qualified art teacher who presumably had private pupils, and in addition to material to illustrate lectures, also provided illustrations for several books.

Professor Beijerinck’s earliest publications (while he was working at the Wageningen Agricultural Collece) were about the improvement of grains for agriculture, and our collection contains a number of drawings of seedheads. Since they are not signed, they could be by Henrietta, or even by Martinus. The image above left shows (clockwise from bottom left) wheat, European spelt and duram wheat. Beijerinck’s doctoral thesis (and a lifelong subject of research) was about plant galls and the collection includes quite a few pictures of galls. The illustration  above right shows moss galls caused by Rhodites rosa gall wasp on young rose leaves.

Henriette also painted assorted microorganisms (see, for examples, the blog post about possible life in comets), but her most beautiful works are the botanic charts. These three images are among the best.

 

Life at comet temperatures

With the increased interest in Comet 67P and ESA’s robot lander, Philae, this seems an opportune time to take a look at a small set of experiments carried out by Prof Beijerinck at the end of the 19th century. During the 1870s, there had been suggestions that life could have come to Earth from comets, but the discussion was largely theoretical until physicists found ways to replicate the temperatures found in space by liquefying gases.

In April 1907, Professor Heike Kamerlingh Onnes of Leiden University gave a demonstration of his new equipment for producing liquid gases (especially hydrogen) at the 11th Congress of the Holland Society of Sciences in Leiden. Beijerinck had been a member since the foundation of the Society in 1888 and it’s hard to imagine that he missed a chance to tour Kamerlingh Onnes’ brand new laboratory. It’s surely not a coincidence that in November and December of that year, he and his assistant, C.J. Jacobsen, took microorganisms from their collection to Leiden in order to test their ability to survive such extreme cold.

yeasts

The experiments were very simple. They used a collection of microorganisms that they knew well, and whose behaviour under normal conditions they could predict. They chose bacteria that could make acid from milk and others that make their own light (bioluminescent), as well as cyanobacteria (also called blue-green algae). Among the “higher” microorganisms were yeasts that can make survival forms called spores, and others that can’t, as well as a couple of fungi which also make spores, and a green alga. Small amounts of each organism (in their growth medium) were sealed in small vials and then frozen in liquid nitrogen (N2; freezes at -195.8°C) or liquid hydrogen (H2; freezes at -253°C) for different lengths of time. The growth and behaviour of the microorganisms were then compared with cells that had not been frozen.

bacteria

The first experiments used liquid N2 (probably because it was easier to produce) for 15 minutes. The second series used liquid N2 for 10 hours or liquid H2 for 45 minutes. The third series involved liquid N2 for 3 and 11 days. Finally, the microorganisms that had survived best were compared in liquid N2 over periods up to 15 days.

alga

There was little difference between the N2 and H2 results – once the organisms were deep frozen, the extra drop in temperature made no obvious difference. The length of time frozen also made little difference. Survival varied with the microorganism involved. The spores of the fungi and yeast that could make them survived, but their active cells didn’t. The bacteria survived. The cyanobacteria all died and the higher green alga survived.

fungi

From these simple experiments, it could be concluded that simple microorganisms such as bacteria and organisms that make survival spores could survive in comets. Beijerinck also commented that extreme cold could not be used as a means of sterilisation.

Deep-freezing microorganisms appears to have been a curiosity for Beijerinck and he does not seem to have returned to the subject. We now know that more complex cells can survive if they are suspended in a solution with suitable protection, and they also do better if they’re frozen and thawed correctly. 100 years after Beijerinck’s experiments, deep freezing (usually in liquid N2) is now used to safely store all sorts of biological material from research stocks of bacteria and viruses to human sperm and tissues.

Celebrating Professors

During the first half of the 20th century, it seems to have been customary to make certificates, posters or books to commemorate special events. The Archive includes a number of photo albums showing laboratories in the University or even abroad, but three examples stand out, not least because of the considerable amount of work that went into them.

The first is a book made for Kluyver by three of his pupils (van Niel, Leeflang and Struyk) a few years after he became Delft’s Professor of Microbiology. The book compares Beijerinck’s 19th century approach to the wonders to be found in 1 gram of soil with Kluyver’s 20th century approach to the wonders associated with 1 gram of carbinol. That’s not students kneeling outside the Professor’s door in the 4th page, but representatives of industry!

1s

04s

05s

2s

The second is a handmade poster (about the size of a large double bed) that was made to mark the 25th anniversary of Kluyver’s inaugural lecture. It shows notable features from those 25 years, including sketches of the laboratory, Kluyver’s most famous work (The Unity in Diversity) and his inaugural address (“Rede”) in which he emphasized the importance of applied research. Every rectangle represents a story.

kly25a

The Kluyver Flask (still used for growing submerged, well-mixed cultures) and a shaker for closed jars containing oxygen-free cultures are shown. During the Dutch “Starvation Winter” at the end of World War II, Delft’s Yeast and Spirits Factory gave their staff soup made from yeast extract at lunch time, and as one of their advisors, Kluyver regularly benefited from this at weekly meetings. Lastly, at a time when it was usual to stand if a Professor came into the room, the staff’s affection for Kluyver shines through in several squares teasing him about his smoking!

A book to mark van Iterson’s 25th anniversary as a Professor also falls into this category despite being essentially a photo album because the makers included all of his PhD students, postdocs and co-workers from other countries, showing who they were, what they did and what happened to them afterwards. van Iterson’s conviction that the primary job of a Professor is to teach is obvious from the fact that there’s 160 pages, each with one or more person on it. The example here shows J.E. van Amstel, the first woman to be granted a Doctorate in Delft.

IMG_0445

amstel

Educational wall charts – where are they now?

During the second half of the 19th century and the early years of the 20th, a number of companies produced wall charts as teaching aids. The theme and quality varied enormously, but most of the ones intended for bioscience education are not only very detailed, but generally beautiful in their own right. They were sold singly, or by subscription. Subscribers were sent the charts as they became available (often 1-2 per year), together with explanatory books.

Delft’s collection includes several complete series, including those by Kny, Dodel-Port and the series known as the Tabulae Botanicae (often attributed to “Blakeslee et al”, but most of the posters are signed by R. Erlich). However, we also have a number of incomplete series which might be represented by a single example, or a few posters. Some complete series are available elsewhere. For example, the conifers chart shown here is number 16 of 50 by Albert Peter – a complete series is held by the University of Bourgogne. However, many seem to have been forgotten.

With the help of collections around the world, it has recently been possible to assemble an electronic complete series of Pfurscheller’s zoological charts (here represented by the fly). Representatives from other partial series are shown here:

The Mycorhiza chart is number 10 from “Pflanzenphysiolgische Wandtafeln” by Frank & Tschirch (we have 1-10 of 60), most of the series is held by the University of Utrecht, among others.

The sweetcorn is number 3 in series C of a set for general biology by Haecker & Mülberger. Series A and B are both currently known by single examples, and Delft currently has 1-4 of series C,  the size of the complete set is unknown.

The flowers come from a set by O.W. Thome (Delft has numbers 15 & 23).

The microorganisms come from a series by W. Henneberg about microorganisms with positive or negative impacts on the fermentation industry. This is number 6, vinegar fermentation. Delft has 8 of an unknown number.

 

Delft’s first microbiologist – Antonie van Leeuwenhoek

Although the Delft School of Microbiology only dates back to Martinus Beijerinck and the late 19th century, it seems churlish to ignore Antonie van Leeuwenhoek on a blog discussing Delft microbiology just because he was 200 years too early. He was not a teacher and indeed actively resisted explaining his methods, but he did publish copiously about everything he saw with his magnifying glasses and simple microscopes, making him the first microbiologist (although not the first microscopist).

Today, van Leeuwenhoek is generally mentioned in connection with the discovery of microorganisms.  However, his studies were much broader than that.  He dissected insects, and examined anything that would fit on his microscope. His first letter to the Royal Society illustrates this clearly as it covers the sting, head and eye of the bee, and the structure of a louse as well as his observations of fungus that he said grew on leather, meat and other things.

Van Leeuwenhoek’s microbiological discoveries began in 1674 when he examined samples from the cloudy water of the Berkelsemeer, a lake near Delft that no longer exists, and found his famous “little animals”. His discovery of bacteria probably dates from his pepper water experiments in 1676, when he reported seeing extremely small animals among the others – a copy of the drawing that accompanied this letter was published by Henry Baker, and is shown here. “Fig IV” is probably the first appearance in print of a bacterium.

Henry Baker s

Baker’s copy of AvL’s pepper water illustration.

 

The film clip here – www.youtube.com/watch?v=OniSF8QrHac – shows what can be seen with facsimiles of van Leeuwenhoek microscopes.

And there’s an excellent website about our Founding Father here: http://lensonleeuwenhoek.net/

© 2011 TU Delft