by Mike Dingley - Australia.

There have been a few microscopes that have been designed and made for specific tasks. One thinks of polarizing microscopes and dissecting microscopes but how many of us know about the Trichinoscope?

Trichinella spiralis is a tiny nematode that is responsible for the serious disease Trichinosis. Humans as well as dogs, cats, rats and hogs can be infected and the cysts are found in poorly cooked pork and dead rats. Nearly 75% of all rats are said to be infected.

LIFE CYCLE.

In pigs adult worms burrow into the mucosa of the small intestine where the female produces larvae. The larvae penetrate into blood vessels and are then carried, via the blood, to the skeletal muscles where they coil up to form a characteristic-looking coiled cyst. This becomes calcified and the adult worms can live here for years if undisturbed. When meat is eaten the trichina enter the stomach and pass into the small intestine and finally into the muscle tissue. Here they live and multiply in continuous series, while the surrounding structures as well as the muscular tissue undergo a process of histolysis. The destructive nature of the parasite is very great. The number of progeny produced by one female may amount to several thousands, and as soon as they leave the egg they either penetrate through the blood vessels or are carried by the circulation until they become lodged in the muscles.

Free Trichinella were seen for the first time by Zenker in 1860 and Rudolph Virchow (1821-1902) succeeded in inducing various German states to make the testing of pig's meat for trichinosis in abattoirs compulsory (c. 1870).
 

MICROSCOPES.

During my research into portable microscopes for a forthcoming book I became aware of microscopes, or more formally called 'Trichinoscopes' which are designed to look specifically for the trichines in meat. Although I have not been able to find out very much information on them I thought that readers might like to read an introduction to these little-known instruments. There may be readers who might be able to pass on to me information on the following instruments and others that I have not included here and I will give full credit where due.

All of the instruments that I have seen have been monocular, low power, compound and having characteristically large stages. The stages hold large double glass plates between which is placed the meat to be examined. One plate has a scale or grid etched into it and both plates can be squashed together using screw nuts on either end of the plates. Compressing the sample makes it thin and translucent.

The earliest instrument that I have managed to find is that depicted in the Billings catalogue in Figure 146, made by Schmidt & Haensch, Berlin in about 1879. It has a horseshoe base, rectangular pillar and stage plate. The stage can be moved in a lateral motion as well as backwards and forwards. Two glass plates 23.5cm X 4.1cm rest on the stage and the lower plate is marked with five 2.54cm squares.

Figure 153, also in Billings, shows an instrument of unknown maker dated before 1880. This instrument has a hardwood base 30.5cm X 10.5cm that also acts as the stage. The two glass-plate compressoria measure 23.5cm X 4.1cm.
 

Winkel-Zeiss (1911-1935) made the Trichinen-Mikroskop as a travelling field microscope. The author has the one in his collection. It is a black and chrome monocular microscope with a large stage (20cm X 9cm). The single plane mirror is on a swinging arm system. The eyepiece is marked T9X and it has coarse focus back rack and pinion. The objective has a RMS thread (S/N 91504) but the barrel is 30mm in diameter and has a lever which allows for two magnifications; 4.5X and 11X. The two glass compressoria are 5mm thick and 23cm long X 5cm wide. One has a grid etched on and are numbered 1-28. The other piece is plain. The instrument is packed in an externally metal-lined wooden case with lid and measures 30cm X 20.4cm X 9.7cm and has a leather carry handle.
 
 

PZO the Polish Optical Company are still making (as at 1999) a small portable trichinoscope called the Mtr. This is a splendid little instrument and has an unusual focussing arrangement. The monocular eyepiece has a knurled ring which, when rotated, gives a zoom magnification of X40-X84. The two part stage folds up to surround the eyepiece and the base has two winged feet which can be pulled out from beneath the base for extra support. The glass plates measure 9.8cm X 4.5cm X .5cm and are etched with two layers of grids marked 1-14. The microscope has a grey plastic top which fits over the microscope and rests on a lip on the base to totally enclose the instrument. The microscope is stored in a brown leather case which also contains the many accessories that will be found useful in the field. The glass plates rest on the two winged-stage which are then raised by hand in order to focus the specimen. The dimensions of this little microscope in its closed form are 3.8cm X 12cm X 12cm.
 
 

H. Hauptner, Berlin-Solingen. Black wooden box 11.7cm X 24.5cm X 13cm with a carry handle. A boss is mounted on the lid. A key lock and key is present under which is a label H. HAUPTNER Instrumentenfabrik BERLIN-SOLINGEN. The end of the hinged pillar slots in to the boss in the case which also acts as the base of the instrument. The single plane mirror is mounted on a yoke.

The black painted-on-brass stage 17.5cm X 7.5cm slides on to a narrow fixed stage plate with dovetail sides. Below this is a circular four hole diaphragm. There are two glass specimen plates 23cm X 5cm X 0.7cm held together with two nickel-plated screws. One plates is engraved with the numbers 1-28 and has H. HAUPTNER, Berlin, NW7 marked. Rack and pinion coarse focus is by a single knob. A single unmarked eyepiece and a non RMS thread objective are present. The objective is unusual in that it has a lower pivoting objective so as to give two magnifications. The case has a small wooden box which contains three dissecting needles in wooden handles. Overall height with the microscope on the case is 35.5cm and wight is about 3kg. The rear of the pillar is stamped TM W1.
 

An instrument has been seen having the name KORTH inscribed on it appears identical to the Hauptner instrument. There have also been seen instruments very similar if not identical to the Hauptner which are unsigned and therefore possibly manufactured by the same company and distributed to various sellers. Without being able to personally inspect these instruments it is very difficult to make judgments on their origins. Another instrument made by MEOPTA in the 1950's has come to light but at this stage the author has not been able to get more information.
 

Comments to the author Mike Dingley welcomed.
 
 

References:
 

Billings Microscope Collection of the Medical Museum of the Armed Forces Institute of Pathology. The Armed Forces Institue of Pathology, 2^nd ed., 1974.
Hickman, C.P., Hickman, C.P. and Hickman, F.M. Integrated Principles of Zoology. 5^th Edition, 1974.
Hogg, J. The Microscope. Its History, Construction, and Application. 15^th edition, 1898.
 

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