Workshop, Berlin, 20- 23 September 2007
Org. by: Ilana Loewy, Nick Hopwood
The first workshop consisted of a hands-on sessions in some historical slides collections in Berlin as well as of round table discussions on the history, the uses, the practical and epistemological value of microscopic slides, as seen from different discliplinary perspectives. The following gives just a very brief excerpt of the discussions, click here for a detailed programme
Discussing images from Koch's "microbe hunting" expeditions to the tropics, Volker Hess showed that the production of slides was sometimes a labour intensive activity that involved travel, danger, and occasionally the use of specific equipment. Slides, especially those produced in field conditions, sometimes became trophies and as such were performative objects that fulfilled specific social roles.
Stephen Jacyna explained that in the nineteenth century, scientists and doctors valued the ability to provide a "good preparation". The acquisition of such a skill was a part of achieving professional status and was sometimes seen as an "entry ticket" to a professional community. Demonstrative slides were used to persuade colleagues that phenomena really exist, and are not merely artefacts or illusions.
Jutta Schikore discussed slides as example for test objects, objects that were used to calibrate instruments and to define the point at which one is capable to separate two points through a higher resolution.
Ilana Löwy discussed pathological slides. For example, differential diagnosis of yellow fever was made on the basis of observation of typical histological changes in the liver. When cytological diagnosis was difficult, slides were circulated to experts abroad; such circulation created a closely knitted international community of specialists.
Gabriel Gachelin drew the attention to slide collections outside life sciences, for example the collection of metallurgic preparations brought from Germany after the second world war by the physicist Yves Rocard.
Drawing on his experience on use of slides in embryology, Nick Hopwood argued that slides may be reluctant objects for the historian. Collections, such as the collection of human embryos at the Carnegie Institute, contain slides, but also catalogues, drawings and three-dimensional models, but it is far from being obvious how to link inscriptions and models to slides. The preparation of serial cuts of an embryo was an important research tool. On the other hand, it destroyed the specimen, and scientists hesitated to destroy rare embryos.
Jean Paul Gaudillière discussed recent collections of biological materials and biobanks in comparison with slides. It may be interesting to investigate what the specificity of slide collections is (if any) , especially in regard of epistemological status of the collected material, its ownership, and its ulterior fate (e.g., when a collection is reclassified).
Denis Lamy described the collections of diatoms slides at the Museum d'Histoire Naturelle, Paris. Diatoms were employed as reference tools in mineralogy and in geology; they provided data on origins of rocks and history of sediments. The introduction of polarized light made possible a detailed observation of their structure. Some media employed for the conservation of specimens destroyed these specimens, others induced important distortions.
Hans- Jörg Rheinberger asked what slides "represent". Are slides "things in themselves", icons, indices, mere preparations? The making of microscope slides involves often a heavy manipulation of the prepared object. A microscope slide still conserves the studied object itself; at the same time, it radically changes this object, transforming it into something very different . The three-dimensionality of the original specimen can be reconstructed using a series of slides, but it is not clear if the reconstructed object is indeed the same "whole".
Slides preserved in collections, Gerhard Scholtz proposed, do not necessarily include items that played an important role in the production of new knowledge. Collections survived when they were useful for teaching or for comparative purposes, or when they had a sentimental or trophy value (collections of known scientists, or specimens brought back from scientific expeditions). Many scientists believe today that it is useless to continue to keep collections of slides: This is regrettable. Important knowledge may be lost when the original slide is discarded and only descriptions, photographs and drawings remain . Going back to the original preparation is a way to check the reliability of other sources of information. Moreover, thanks to the use of modern techniques historical slides can sometimes be used to retrieve new data.
Naturally, scientists, curators and historians of science have different points of view on slides. And slides used for routine investigations or for teaching may be quite different from unique preparations that display skills and aesthetic values of their makers. Perhaps one should not speak about a single object "the microscopic slide", but distinguish among several classes of such objects.
The Workshop proposed to see slides as intermediary objects, on the boundary between the raw material and a finite scientific result. Slides incarnate both the materiality of the original, and the labour necessary in its transformation into a scientific object. This intermediary status of the microscope slide may differentiate them from other, less processed objects found in collections — but perhaps also from other preparations, more remote from the original specimen. Perhaps slides are a distinct category of scientific objects, and we need specific methods to study them.
Slides can be viewed as intermediary, "in between" objects, a technological interference between the microscope and the organism that produces specific, and perhaps sui generis effects. Preparations are highly artificial, but, because they conserve the materiality of the studied item, they are also seen as "natural objects". They may be seen as intermediary products of scientific activity, as complex inter phases between different technical aspects of manufacturing preparations, and as objects that produce specific effects.
In "slide rich" scientific domains, microscopic preparation may become the backbone of a network that links experts , but also provide the link between heterogeneous scientific communities: those who collect specimens, study them, conserve them, use them for teaching (e.g. explorers, laboratory scientists, curators—or surgeons, pathologists, teachers).
In life sciences, one should perhaps speak about the "golden age" of the microscope slide—late nineteenth and early twentieth century. The main technical innovation (cutting, fixing, staining) are originated from that time, and in some areas, these techniques are conserved until today (e.g. surgical pathology). The impressive size of some museum collections of slides reflect the importance of slides at that time as key repositories of knowledge.