ABSTRACT
Under one and the same heading we must here consider certain theories which seem to differ, but in reality have a common basis. Descartes, by reviving the Galenic theory of the vital spirits, which he understood in his own particular way, had unintentionally dealt a severe blow to Iatro-mechanics, for he thus brought back into science the idea or force which he had tried to exclude from his own mechanical theory. The discovery of electricity just at the time when Willis and Lower were tracing disease to the nervous system, when Croone was explaining muscular movement by the effervescence of a nervous fluid and Cole was talking of nervous tension and Glisson of irritability or a principle of energy, created a current of opinion in favour of a particular nervous force. This idea was strengthened by the publication at the beginning of the XVIIIth century of Newton’s theories, which admitted distinct forces in nature under the names of attraction, gravity and light. At the same time Stahl’s theories of tonicity and phlogistics, von Goiter’s and Whytt’s (his disciples) attribution of the movements of the body to the stimulation of Baglivi’s motor fibre, and Hoffmann’s opinion as to the spasm of the fibres and vessels, caused a tendency towards ‘ neurosism ’.
