The transmission of the nervous impulse is always from the dendritic branches and the cell body to the axon or functional process. Every neuron, then, possesses a receptor apparatus, the body and the dendritic prolongations, an apparatus of emission, the axon, and the apparatus of distribution, the terminal arborization of the nerve fibers. I designated the foregoing principle: the theory of dynamic polarization (Cajal 1923). Ever since the beautiful drawings from Golgi and Cajal, we have been familiar with the organisation of neurones into dendritic, somatic and axonal compartments. Cajal...