Posts in category G. van Iterson jr

Material relating to van Iterson’s work and/or lab

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.


Glass negatives galore!

Small projector set up for glass negatives.

Small projector set up for glass negatives.

Glass negatives.

Glass negatives.


Our glass negative collection (about 27,000 of them) dates from the mid-1880s to the 1960s (when they were being used with the electron microscope. It covers a remarkably wide range of topics including Beijerinck’s gall wasps, light microscopy, travel (especially van Iterson’s working trip to Indonesia) to images from publications – essentially what any group of Professors would have in their Powerpoint collections today. The quality of the images is amazing – it has been possible to enlarge pictures to A0 without grain or blurring.

Later posts will showcase the individual collections of the three Professors, this is just a taster to show examples of what we have.










Brendel flower models

The collection includes about 20 of the flower models made by Robert and Reinhold Brendel in the late 19th and early 20th centuries. The models are made from  papier-mâché with other materials including plaster, glass beads, wood, cotton and rattan added to give detail or texture. They can be taken apart to reveal internal details (although they’re not always simple to put back together again). The Brendels were advised on the accuracy of their models by various Professors, depending on what the particular model was intended to show. As well as plants, models of fungi, yeast and bacteria were eventually included.
Dealers included the models in their own catalogues, but Delft has the only known surviving Brendel catalogue, issued in Berlin in 1913.

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