In the 19th century progress in communication systems induced Hermann von Helmholtz and Emil du Bois-Reymond to compare nervous fibres to telegraph wires aiming to familiarize the neural net already independently described. Owing to neurophysiological developments, this metaphorical way of speaking collapsed. In the 1820's Edgar Adrian chose the Morse code, shifting the paradigm from a mechanical to a semantical model: the fibre served to communicate information by means of a code based on frequencies of impulses. Later the term neural code became simply a metaphor, thus helping to fill a cognitive gap: this move, however, could lead to snags neurophysiologists might encounter adopting it. (Armando De Palma and Germana Pareti)