Molecular Dissyimiietry. ] 3 



invalidates Pasteur's provisional generalisation, that the 

 natural rotation is an unfailing expression of a molecular 

 condition produced only in the laboratory of life. In the 

 first place it must be borne in mind that the state induced 

 by the magnetic force is a state of tension which disappears 

 instantly the magnet is removed ; the state of molecular 

 dissymmetry is not a state of tension, but the permanent 

 state of the molecules themselves, requiring no outside sus- 

 taining influence. The rotatory power of the magnetized sub- 

 stance is exerted in only one general direction, that of the 

 line of magnetic force ; pass the beam of light through the 

 substance in any other direction and it will be unaffected. 

 The rotatory power of the natural state is exerted in every 

 direction, the only limitation being that the rotation is 

 always in the given substance either to the right or left of 

 the observer. With this limitation the natural substance 

 will simultaneously rotate the plane of rays of light which 

 are passing through it in all directions. All this is 

 clearly pointed out by Faraday. " The direction of the 

 rotation produced by the natural state," he observes, 

 " is connected invariably with the direction of the ray 

 of light ; but the power to produce it appears to be 

 possessed in every direction and at all times by the par- 

 ticles of the fluid ; the direction of the rotation produced 

 by the induced condition is connected invariably with 

 the direction of the magnetic line or the electric current, 

 and the condition is possessed by the particles of matter, 

 but strictly limited by the line or the current, changing and 

 disappearing with it." I submit that the molecular condi- 

 tion of a substance which at a given time, under tension 

 only, can exert a given power in only one direction is not 

 the same as that of a substance which at any moment, 

 without tension, can exert the power in every direction. 

 The difference appears as profound as that between the 

 limited motion of the steam-engine and the infinite mobility 

 of the living organism. 



