NO SUCH THING AS VITAL FORCE. 221 



theory of Fletcher will, I think, be made more plain 

 in reviewing, in the same sense as Dr. Beale, the 

 physico-chemical theories of a vital force supposed to 

 be correlative with the physical forces. Professor 

 Owen speaks of vital modes of force correlative with 

 physical and chemical modes of force, and conveys the 

 idea that otherwise inanimate matter of the tissues, 

 for example can show the phenomena of life when 

 under the influence of these forces, and cease to do so 

 when they are withdrawn, just as a piece of steel may 

 act as a magnet or not. This same idea, although not 

 so openly expressed, pervades the ordinary physico- 

 chemical school, who are not prepared to allow that 

 the proximate principles do not exist as such in the 

 protoplasm. But apart from the origin of these pecu- 

 liar forces, it is easy to show that nothing of the nature 

 of a force can possibly have the power attributed to 

 them. For, in the case of harmonic vibration, as when 

 a bell or stretched wire gives out the same note that is 

 sung or played, the force of the sound- vibration of the 

 air passes to the bell or wire, which is capable of vibra- 

 ting at the same rate. In this case the strength of the 

 voice sound is weakened by exactly the amount of 

 force transferred from the aerial vibrating particles to 

 the solid ones. Precisely the same happens when par- 

 ticular light vibrations are intercepted by harmonically 

 vibrating gaseous particles in the phenomenon of spec- 

 trum analysis. The same happens in the radiation of 

 heat, and numerous other examples. In all these there 

 is simply a transfer of force. But in magnetization of 

 iron by blows, or the development of heat or electricity 

 by friction, or in fluorization, there is also transformation 



