Hydrous piceus, the largest water beetle in Europe.

The Somso Comp. made replicas of the famous Ziegler Models in 2002. Catalogue Card of the Zoological Teaching Collection

A microtome is a mechanical instrument used to cut biological specimens into transparent thin sections, to be put on a slide. Steel blades are used to prepare sections of animal or plant tissues.

Transparent microscope preparations intended for teaching need special treatment: Especially preparations made with glycerol often were fixated with a thin layer of lacquer, applied with the help of this machine.

Hidden treasures: Working material of the Zoologist Karl Heider, Head of the Teaching Collection, was handed down to his successor...

...and turned out to be a slides collection, working material for his latest book.

From Slides to Digitalized Images: Longisection of an embryo of a hydrous piceus, made by Karl Heider

Phases of the development of the Hydrous piceus: Karl Heider had made drawings from slides, which later became the basis for wax models by the famous Ziegler company. (Replicas by Somso)

Early form of the limb of the Hydrous piceus, Wax model by Ziegler 1890. (Replica by Somso)

Wax Model of the phases of development of the Hydrous piceus: Stigma

Back to 2 dimensions...Cataloguing the Somso Modells

Slides' neighbours and relatives: The Zoological teaching collections houses also 600 wall charts, among which are some by the famous Leipzig Zoologist Leuckart.

The Zoologist Karl Heider started his career working on the hydrous piceus. Later in his life he became professor in Berlin and Innsbruck and a member of many well known societies.
Shortlist of his titles in his own handwriting. In: Ulrich, W.: Karl Heider, 1856-1935. Studium Berolinense. 1960, S. 868-897