This article is dedicated to the history of the Steindorff "Microbe Hunter", a 20^th century microscope with a fascinating design (fig. 1 - 4), appreciated by collectors as one of the most beautiful and elegant microscopes ever made.

Figure 1 - 4: The Steindorff "Microbe Hunter". Instrument # 540671, made in 1954.

The Steindorff Company¹ was founded in Berlin, Germany, in 1879² . Serial numbers³ , catalogue claims⁴ and the frequency of today's internet auction sales suggest that at least 100.000 professional microscopes left the Steindorff workshops until to the end of production in the 1980s. So we do have abundant evidence testifying the existence and productivity of the company. On the other hand printed sources are extremely scarce.

Within the current international reference literature about microscope makers, Steindorff is not present at all. Even in Germany it has left very few paper traces⁵ , mostly sales catalogues and a small user's manual which was reprinted over decades with only minor revisions (fig. 5).

Figure 5

Due to the courtesy of the private Steindorff archive we are able to present documents illustrating the activities of the company at the time period when the The Microbe Hunter microscope was invented, constructed and produced (ca. 1947 - ca. 1960). We will have a closer look at one of the surviving instruments and discuss the popular name. It will be noted that the Microbe Hunter played a significant role as a prop in the dramatic doctor film "Dr. Holl". Last but not least the instrument can be used to illustrate the challenges which a small optical company had to overcome in order to survive besides the Zeiss and Leitz giants, and even prosper in this difficult landscape and extending to the U.S. market due to a favourable currency conversion rate.

Description of the Microbe Hunter

The following description refers to instrument no. 540671 produced in 1954. The trinocular double-arm stand (see also fig. 6) is made up of one solid piece of cast metal. The overall dimensions⁶ and the mass of 9.6 kg⁷ provide excellent stability to the microscope, even for photographic work.

Figure 6 and 7

The coaxial combined focussing gear as introduced by Zeiss in 1950⁸ obviously is not yet present here. Instead we find separate coarse and fine focussing wheels
(fig. 7) which serve to adjust the level of a square 15 cm x 15 cm mechanical stage with verniers for x and y movement. The substage is equipped with a triple nose condenser revolver (fig. 8) bearing three condensers for low magnification, high magnification and dark field. Furthermore there is a de-centerable aperture iris for oblique illumination. Electrical illumination is provided by a low-voltage lamp with collector lens and iris (fig. 9) fed by a massive transformer, 10 cm in height (fig. 10) which provides currents up to 5 A / 6V (30 W). The six objectives⁹ (fig. 11) are achromatic, colour coded, and have internal 3-point centering devices. None of them has a spring protection. The colour codes on the objectives correspond to the colour codes on the sixfold nosepiece. A straight photo tube¹⁰ can be fitted on top of the instrument.

Figure 8

Figure 9

Figure 10

Figure 11

There were some minor changes and improvements over the years but obviously all Microbe Hunters form a uniform group far distinct from all other microscopes.

An unusual name for an unusual microscope

Microscope names tend to be short and soberly technical, e.g. "Model 320c",
"Type T.C.Y.N" or simply "No. 3220". Sometimes the price class will shine through a little bit by means of attributes like "Standard Junior" or "Universal Scientific Microscope". Everything beyond this terminology might appear to be indecent for the scientific world.

So we come to the conclusion that the name "Microbe Hunter" is a little bit bolder, a little bit venturesome. We do not know how this name has been chosen. Obviously, a small enterprise like the Steindorff Company had no public relations and advertising department in the modern sense of the term; the few surviving printed Steindorff documents indicate a communication style which might be characterized as extremely laconic at best. The economic situation of the Steindorff company in post-war Germany apparently was far from paradise. The workshops were situated in a modest, single rented floor of an apartment house in the city.

But when the Microbe Hunter came out it was presented proudly on trade fairs in the United States, advertised in Germany and, as we will see, and even positioned in a movie. The inventor of the Microbe Hunter, Julius Kaiser, was already in his late 60s when he came up with his revolutionary dream of an instrument. The enormous pride shining through the lines of the U.S. catalogue is evident, boasting with terms like:

-- "we herewith have much pleasure of calling your attention to a novel microscope, developed in many years of constructional labour",

-- "the instrument joins all the characteristic features of modern microscopes but is deviating from hitherto known types",

-- "the MICROBE HUNTER - the most modern microscope ever designed"

Obviously Julius Kaiser had put his personal dream to reality and therefore didn't choose a lightweight name for his product. For sure it is no coincidence that each of the three surviving workshop photographs is dominated by a Microbe Hunter. Like in the "Dr Holl" film there seems to be always some emotion and positive affection linked to the instrument. The name "Microbe Hunter" is clearly connected to Paul de Kruif's famous popular book "Microbe Hunters" which appeared for the first time in 1926. The book contains a collection of short reports describing the life work of famous bacteriologists like Louis Pasteur and Robert Koch. "Microbe Hunters" quickly became a bestseller though analysts would never have believed that the world of microbes might interest anybody beyond the scientific scenery. Even today "Microbe Hunters" can be recommended as a rewarding literature, in particular because of its brilliant mixture of thrill, easygoing style and sometimes cynical irony. It is difficult to tell today whether such a glamorous name might have been an incentive for the typical customer to buy or whether it might have sounded a little bit too luxurious e.g. to the ears of the financial boss of a hospital.

Glamour ... the Microbe Hunter as an actor in the tear-jerker movie "Dr. Holl"¹¹

The Microbe Hunter can be seen several times in the Dr Holl film (fig. 12, fig. 13).

Figure 12

Figure 13

The plot of the film is as follows: Angelika, the beautiful daughter of the rich industrialist Alberti has fallen seriously ill from the mysterious "Miller's Disease". Her life expectancy is a few weeks only. Alberti calls for assistance the handsome and energetic Dr Holl who currently investigates Miller's disease. Dr Holl informs Alberti that his scientific work is still at the very beginning. Nevertheless Alberti offers to finance a dedicated laboratory at his luxurious lakeside, Italian-style holiday villa. A little bit later Dr Holl is shown within a dream of a laboratory, built like a winter garden, working with the fashionable Microbe Hunter and hugging the attractive nurse Helga.

Even the original wooden transport box of the freshly unpacked Microbe Hunter is visible in the background. Angelika falls in love with Dr Holl and Alberti asks Holl to enter a sham marriage with Angelika for a few weeks in order to console her.

Nurse Helga is not amused. Dr Holl is working hard all day and night and finally discovers a serum against Miller's disease. Dr Holl's results are checked by his teacher, a senior professor who peers - in a grim manner - through the Microbe Hunter as well. Though apparently focusing only to the outer edge of the specimen slide at a very low magnification, the professor is very much impressed by the microscopic evidence indicating an important discovery. Due to Dr Holls’ brilliant research, Angelika recovers from Miller's disease and now Dr Holl falls in love with her as well. In the meantime nurse Helga studies medical arts, gets a Ph.D. very quickly and is consoled by a medical director's position financed by Alberti. Far from reality? Well, we do have doctor's romances even today.

A favourable dollar-DM conversion rate: trying to enter the U.S. market

We know from the Steindorff archives that many Steindorff laboratory microscopes of the classical type have been sold to U.S. universities and U.S. hospitals in the late 1950s and 1960s. During this period the north American representative of Steindorff, J. Beeber, sent a series of sales reports and technical evaluation reports to the mother company in Berlin¹² .

But there is very little information about the earlier (and probably very rare) Microbe Hunter exports to the United States. The authors were not able to find an U.S. price list which might help to fit the Microbe Hunter into the U.S. microscope sales hierarchy.

The few remaining U.S. folders and a Steindorff catalogue of about 1950 (all without price lists) present the Microbe Hunter as the extraordinary flagship besides a series of routine instruments. The sales code word for of a fully equipped Microbe Hunter with six objectives but without electrical illumination in those catalogues was "BIVIR", sometimes "BIVIER" (fig. 14 - 16).

Figure 14 and 15

Figure 16 and 17

Within the Steindorff files there is a price list (fig. 17) handwritten on the reverse of a KLM flight journal with date February, 1st, 1951. It reads "BIVIER $300, BITRE 282, BIZWO 283, BIMON 270 ..." which indicates that the highest sales price or possibly reseller price, the price for a fully equipped Microbe Hunter, was only $300 US.

The first document referring to the planned foundation of a "Steindorff of America" company dates back to end of January 1951 (see fig. 18). This "memorandum"¹³ specifies a catalogue price of $300 US for the most expensive Steindorff microscope, again the Microbe Hunter, which would have been a very competitive price in the United States.

Figure 18 and 19

At that time the US-Dollar/DM conversion rate was 1 : 4.20 and was therefore ideal for an export from Germany to the United States. The respective German price for a Microbe Hunter with six achromatic objectives would have been 1,260 DM.
For comparison, in the year 1952 the price of a typical Zeiss Lumipan¹⁴ (see fig. 19) in Germany was in the range of 2,000 to 2,500 DM.

The "Microbe Hunter" concept - how to legally protect an idea situated somewhere between design and technology¹⁵

It is not precisely known up to now at which time the idea of the "Microbe Hunter" design emerged. But there are convincing reasons to assume that the plans were fully enacted in 1948 or early 1949. Among the few known existing workshop photographs is an image showing a person with pencil and cigarette bending over a diagram showing the "Microbe Hunter", with the diagram lying on a workbench (fig. 20, fig. 21).

Figure 20

Figure 21: enhanced detail of figure 20. The upper parts of the curved arms of the Microbe Hunter are visible

The person shown is possibly one of the members of the Kaiser family who were the owners of the company at that time, perhaps Julius Kaiser, born in 1883, who was officially named as the Microbe Hunter inventor by the Steindorff company. On the photograph are many classical microscopes, apparently in different stages of assembly, positioned close to the plan, most of which seem to be from early post-war production, with many coarse focussing knobs in modern shape and finished in chrome but at the same time with a few knobs in black finish which must be attributed to times of lacking chrome resources, i.e. probably produced during or shortly after the Second World War.

A Microbe Hunter photograph apparently has been shown at the Museum of Science and Industry, New York, in the period between April 9th 1949 until April 24th 1949. Within the Steindorff files there is a document by the U.S. Military Government of Germany certifying that Steindorff Company showed a "Microbe Hunter" photograph at the exhibition (fig. 22). So we can be sure that at least one "Microbe Hunter" must have existed in 1949.

Figure 22 and 23

There is evidence of a second early participation in an U.S. exhibition, namely the "First United States Trade Fair" held August 7th to 20th, 1950 in Chicago, Illinois but we do not know whether a "Microbe Hunter" was actually shown there.

Furthermore we have a short article¹⁶ in the German microscope amateurs' magazine "Mikrokosmos" reporting that the Steindorff company presented the new "Microbe Hunter" at the 70th anniversary of the company which was in the year 1949 - the company was founded in 1879.

From the very beginning it seems to have been clear that some kind of legal protection was absolutely necessary in order to prevent unauthorized copies of the new microscope concept. Ironically it became clear later on (one decade later) that the U.S. and German customers really loved the Steindorff microscopes with the traditional heavy stands in classical design (fig. 23). Instead, it appears that only very few Microbe Hunters have been sold.The Steindorff company became famous for its classical metal craftswork and for its solid parts turned out of massive steel.

Basically, the Steindorff company followed two parallel routes in order to achieve a legal protection of the "Microbe Hunter": the protection of the technology (rigid stand with fixed geometry, prism switch technology, improved ergonomics) on one hand and the protection of the design on the other. Most of those legal activities occurred within a few days in early April 1949, possibly because the first "Microbe Hunters" had been assembled at this time, but this is just a hypothesis.

Only one day before the presentation at New York, on April 8th, 1949 the company requested a patent protection at the West German Patent Office in Munich. The four figures illustrating the request (fig. 24 - 26) show an ingeniously simple mechanism with a single prism for the change between binocular and monocular (photographic) use.

But there was a protest by the Leitz company against the patent claim (date July 24, 1951). The line of thought behind the Leitz protest was that they offered trinocular microscopes as well and that it was not an improvement to have the trinocular head irreversibly fixed to the stand. Finally the West German Patent Office rejected the Steindorff patent claim on Feb. 23, 1954. A parallel patent claim for Eastern Germany had already been rejected one month before, on Jan. 5th, 1954. In the end the patent pathway had turned out as an expensive failure. There are many letters within the Steindorff files discussing the regular money transfer from the company to the patent lawyer.

Figure 24 (prism in vertical position)

Figure 25 (prism in horizontal position)

Figure 26

Figure 27

In contrary to this initial patent failure the national and international design patent seems to have been much a success. A first attempt for a national design patent to a Berlin-Charlottenburg court dates back to May 27th, 1948 but apparently it was not accepted. A second attempt followed in April 1949. The international design patent was accepted by the "Bureau international de la Propriété International", Bern, Switzerland, No. 12272, on May 7th, 1949 for five years and seems to have been updated until to the year 1964.

In the defining text the Steindorff company stresses that their specific success was to provide their microscopes with a completely new and aesthetic visual appearance. Today we might have the feeling that many of the following modern microscope designs, also by other companies, were definitely inferior in design quality.

How a small company made its own microscope objectives

Some very interesting documents within the Steindorff files refer to lens construction (see example of an optical calculation in the fig. 27). Apparently the Steindorff company employed a freelance mathematician, Mrs Käthe Gallus in Berlin, who calculated the optical components of the objectives. Her task included the calculation of the overall geometry, the lens radii, the lens diameters and distances and the definition of the glass types to be used.

The blueprint dated 6th Sept. 1949 refers to a Steindorff achromatic 45x objective with an N.A. value of 0.85. The objective is made up of 5 lenses combined to three elements. A hypothethic cover glass is included in the calculation. The diagram and the table contain all the necessary lens dimensions, lens distances and glass specifications. Even the small spaces between the individual elements (0.1 mm) are indicated. The numbers along the optical axis of the objective refer to the respective lens thicknesses which can be found also in the 3rd column of the table ("Dicke", i.e. thickness). The 2nd column lists the lens curvature radii, positive values for convex curvature and negative values for concave curvature. The 4th column defines the free diameters, i.e. the optically usable cross-sections of the lenses within the objective. And finally, the last column states the glass type and the order specification. All values are in mm. The outlines of the lenses have been enhanced by the authors. The next step for the Steindorff company was then to order the lenses from the optical glass producer and to build a metal case with the appropriate fittings around the lenses.

Summary

It is impressive to learn how a rather small company tried to turn classical microscope design upside down and to sell successfully its products overseas. The workshop photographs (see last figure 28) prove that the management and the owners of the company were passionately dedicated to their product.

Figure 28

There were no external consultants or controllers around, not a single computer or a mobile phone but instead lots of energy by relatively few persons directly invested into the product. For example there are five different massive metal labels on the Microbe Hunter transformer alone, each ot them neatly punched, coloured and kept in place by rivets.

In the long run the Steindorff company had its commercial success - though not as planned with its design dream but with its solid classical instruments which have been used for decades in many countries.

Additional information and comments to the authors are welcome.

Foto credits:

Private Steindorff archives: 17, 18, 20, 21, 24, 25, 26, 27, 28.
Steindorff manual: 5, 6, 23.
Steindorff catalogue: 14, 15, 16.
Zeiss Jena catalogue: 19.
Martin Mach: 1, 2, 3, 4, 7, 8, 9, 10, 11.

Footnotes: (Click footnote number to continue reading article.)

1 The most used official name was "Optisch-mechanische Fabrik Steindorff & Co."

2 According to many references in Steindorff catalogues.

3 Steindorff serial numbers exceeded the 50,000 mark already before the Second World War. After the Second World War, ca. 1950, and short after serial number 60,000 a new notation was introduced: those post-war serial numbers consist of six digits the first two of which indicate the production year and the following four the instrument number within the respective year. So e.g. serial number #780284 can be deciphered as instrument no. 284 of production year 1978.

4 For example in a "Conatex" catalogue distributed in the 1980s.

5 A Steindorff Microbe Hunter has been mentioned and depicted in the German microscopy textbook: Ludwig Otto, Durchlichtmikroskopie, p. 56. Berlin 1959.

6 Width 21 cm, depth 32 cm, height 33.5 cm (measured to the upper level of the eye-pieces).

7 Weight with optics but without electrical illumination.

8 F.K. Möllring: Mikroskopieren von Anfang an. Without date. Ca. 1970.

9 4x (-); 10x (N.A. 0.30); 30x (N.A. 0.45); 45x (N.A. 0.65); 60x (N.A. 0.85), 100x oil (N.A. 1.30).

10 The light is directed either completely to the binocular head or completely to the straight phototube.

11 "Dr. Holl" movie, 1951, with famous German actors Dieter Borsche (Dr. Holl), Heidemarie Hathayer (nurse Helga) and Maria Schell (Maria, victim of Miller's disease).

12 One of those documents with date 6-25-58 states that a Steindorff BF-KM-40 with serial no. 580135 had been sold to the University of Pennsylvania and there is a comment on the copy that the Department of Surgery of the Unversity of Pennsylvania at that time was headed by Dr. Radvin "who is well known for his outstanding performances on both President Eisenhower and Secretary of State, John Foster Dulles."

13 Translation of the marked section: "The first order with code BEVIER will include 100 microscopes and will be based on the fact that the catalogue price by Steindorff is $300.-- and that the other instruments will have respective prices."

14 The binocular research microscope Zeiss "Lumipan" with four achromatic objectives and with a pancratic triple revolver condenser sold for 2.136,50 DM in 1952 (source: price list CZ 30-126a-1 by Zeiss-Jena with date March 1st., 1952).

15 Credit: also this information is due to the generous support by the private archive of the Steindorff company. As it was not possible to find an eye-witness of the early "Microbe hunter" period at the Steindorff Company, this article had to be based solely on the written documents within the Steindorff Files.

16 Horst Kaudewitz: Forschungsmikroskop "Mikrobenjäger". Mikrokosmos 41 (1951/1952) p. 187.

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