The microscope is signed on a plaque attached
to the tube Ed. Messter, Berlin, N.W.. It has a serial
number, 31416, engraved on the back under the stage. It is an example of Messter's
Universal Bacteria Microscope. The construction of this
microscope is unique. There is no actual coarse focusing
adjustment, only a fine adjustment by micrometer screw that raises or lowers the objective turret. There
is a spring loaded lever mechanism actuated at the back of the limb that is used to
slightly raise the objective turret for changing objectives. The turret snaps
back to the previous postion when the lever is released. The fine adjustment
and the lever mechanism work on the same spring located within the tube.
This microscope and its lenses were constructed to be parfocal when changing
the objectives and eyepieces for each of the nine possible combinations.
The microscope measures about 15-inches tall in the upright position as shown in the photos.
It is constructed in brass with a painted cast iron base.
The following was extracted from Journal of the Royal Microscopical Society, 1898
Messter’s Bacteria Microscope. — The makers of this instrument
claim that its specially advantageous construction almost
entirely removes troubles arising from loss of time (1) in
changes of eye-pieces and objectives; (2) in tedious coarse
adjustment for various powers; (3) in laborious picking out
of very minute objects with strong magnifications. Investigations
can therefore be made, even by a tyro, more quickly, accurately,
and conveniently, with this instrument than with any other.
It is specially recommended to physicians for diagnosis of
urine and sputum. The figure (101) shows clearly the arrangement
of the eyepieces and objectives with their revolvers; and
the fitting of these is so perfect that the image is always
adjusted for every nine magnifications. [Thus apparently
no coarse adjustment is required.— ED] An improved central
micromillimetre-screw secures the fine adjustment; and a
lever under the micrometer-screw effects a raising or lowering
of the tube without change of adjustment, which is very
convenient in the application of thick-ringed slides, or
in the rotation of the objective revolver.