476 SCIENTIFIC THOUGHT. 



course of more than a centurj, alternately taken up 

 with enthusiasm, and abandoned as misleading. At the 

 turn of the centuries the mania for animal electricity 

 was at its height. Men like A. von Humboldt took up 

 the study with eagerness, and sovereigns like Napoleon 

 offered special prizes, in the hope that here at last the 

 secret of life and consciousness would be revealed. The 

 school of the " Naturphilosophie " in Germany seized 

 upon the suggestion of polarity and polar forces con- 

 tained in the phenomena of galvanic action, and, sup- 

 ported by the still more mystical processes of the 

 so-called animal magnetism which had been exhibited 

 by Mesmer twenty years earlier, worked up these 

 vague indications into fanciful theories of vitalism and 

 animism. This brought the whole line of thought 

 into discredit, drove away the soberer, more scientific 

 students of nature, and retarded real progress in the 

 knowledge of the electric phenomena of the muscular 

 and nervous system for fully a generation. At length 

 in the school of Johannes Mliller the subject was again 

 approached and was put on a firm scientific basis by 

 Helmholtz, and notably by Du Bois - Eeymond. It 

 is now known that, as in inorganic, so also in organic 

 systems, the energy proper to them can appear under 

 the different forms of mechanical, thermal, electric or 

 chemical energy, but also that in none of these can be 

 found pre-eminently the principle of life, still less that 

 of consciousness. 

 10. Another important line of research which has had 



an equally fluctuating development, being sometimes 

 enormously exaggerated, to the damage of sound pro- 



