In some cases our sensory organs are no longer capable of rendering processes in the external world perceptible to us. Their inadequacy expresses itself, for example, in phenomena that involve the kind of expansion of space and time in which the conditions for summary perception are no longer at all present. The resources that aid our immediate sense perception in these circumstances will thus be charged with the task of expanding or diminishing space and time to the extent that the contiguity and succession of events is comprehensible to us. The microscope is thus essentially based upon the principle of spatial expansion, the map on that of spatial diminution. The pertinent contrivances for these purposes are largely derived from the graphic arts. How stereoscopy and instantaneous photography, which is based on temporal expansion, facilitate our perception! In spite of the multifarious applications of photography, one has yet to take the step of employing it in the opposite direction, namely as a means of temporal diminution. We demonstrate that phenomena that take place in too ephemeral and too rapid a succession for our eyes can, with the help of instantaneous photographs in series, be analyzed with our senses as the event passes in a comparatively longer time. Quite analogously, we could also compress into a small duration the moments of an event separated widely from one another in time and thereby give our perception an understanding of the nature thereof.

This paper focuses on the uses of electroencephalograms (EEGs) in Mexico during their introductory decade from 1940 to 1950. Following Borck (2006), I argue that EEGs adapted to fit local circumstances and that this adjustment led to the consolidation of different ways of making science and the emergence of new objects of study and social types. I also maintain that the way EEGs were introduced into the institutional networks of Mexico entangled them in discussions about the objective and juridical definitions of social groups, thereby preempting concerns about their technical and epistemic limitations. This ultimately enabled the use of EEGs as normative machines and dispositifs. To this end, the paper follows the arrival of EEGs and the creation of institutional networks then analyzes the extent to which the styles of thinking behind the uses of EEGs and attempts to reify a notion of normal electrical brain behavior—particularly by applying EEGs to a community of Otomí Indians—correlated with the difficulties of defining the socio-anthropological notions that articulated legal and disciplinary projects of the time. Finally, it unveils the shortcomings of alternative attempts to define a brain model and to resist the production of ontological determinations.

In this paper, I argue that studying school textbooks is a fruitful way to investigate mathematical conceptions in different national contexts. These sources give access to the written production of an extended mathematical milieu whose members write for various audiences. By studying the case of late 1950s French and English textbooks issued for a growing audience of 11- to 15-year-old pupils, I show that a plurality of conceptions was projected at the time onto pupils and their teachers in both national contexts. I link this diversity to contemporaneous debates regarding mathematics teaching and argue that textbooks themselves have to be considered as active agents of such debates.

In the above mentioned article [1] unfortunately the names of the translators of Toeplitz's lecture were omitted. The correct title is:

The Problem of University Courses on Infinitesimal Calculus and Their

Demarcation from Infinitesimal Calculus in High Schools

Otto Toeplitz

Translated into English by Michael N. Fried and Hans Niels Jahnke