Contains first reference to experimental work on the motor functions of the ventral spinal nerve-roots, without, however, establishing the sensory functions of the dorsal roots. This very rare privately printed pamphlet, the original edition was limited to 100 copies, is reproduced in Medical Classics, 1936, 1, 105-20. Facsimile reprint, London, 1966. Bell’s own annotated copy, preserved in the library of The Royal Society, is reproduced in Cranefield, The Way In and the Way Out: François Magendie, Charles Bell and the Roots of the Spinal Nerves, Mt. Kisco, N.Y., Futura Publishing, 1974. See No. 1588.9. Cranefield proves that Magendie (No. 1256) discovered the “Bell-Magendie law”.