Beyond the Temples of Science - continued...

The Brain's Switching Apparatus

In contrast to the flowery style of his memoirs, Schleich expressed his idea about the function of neuroglia in the prosaic terms of contemporary neuroscience in his Schmerzlose Operationen (Painless Operations, 1897). The neuroglia, Schleich argues, is the inhibiting substrate, the modulator of inhibition in the brain. The terminal branches of the neurons merely approach each other, "and in between them lies precisely the isolating substance of the neuroglia." Inserted between the neurons (and their appendices), the neuroglia supplied a switching mechanism which organized and regulated the ebb and flow of nervous excitations. Consequently, the glial cell was an "actively functioning substance" just like the neuron, a cellular element which plays an active role in psychic events (All citations Schleich 1897, pp. 86-87).

A more realistic view of the cells in the brain. Neurons (marked with an arrow) and glial cells are stained by a silver impregnation method. From Retzius 1890-1914, vol. 6, plate ix.