82 . FRAGMENTS OF SCIENCE. 



grees of complexity. Men of science avail themselves 

 of all possible means of exploring their molecular archi- 

 tecture. For this purpose they employ in turn, as 

 agents of exploration, light, heat, magnetism, electric- 

 ity, and sound. Polarised light is especially useful 

 and powerful here. A beam of such light, when sent 

 in among the molecules of a crystal, is acted on by 

 them, and from this action we infer with more or less 

 clearness the manner in which the molecules are ar- 

 ranged. That differences, for example, exist between 

 the inner structure of rock-salt and that of crystallised 

 sugar or sugar-candy, is thus strikingly revealed. 

 These actions often display themselves in chromatic 

 phenomena of great splendour, the play of molecular 

 force being so regulated as to cause the removal of 

 some of the coloured constituents of white light, while 

 others are left with increased intensity behind. 



And now let us pass from what we are accustomed 

 to regard as a dead mineral, to a living grain of corn. 

 When this is examined by polarised light, chromatic 

 phenomena similar to those noticed in crystals are 

 observed. And why? Because the architecture of the 

 grain resembles that of the crystal. In the grain also 

 the molecules are set in definite positions, and in ac- 

 cordance with their arrangement they act upon the 

 light. But what has built together the molecules of 

 the corn? Eegarding crystalline architecture, I have 

 already said that you may, if you please, consider the 

 atoms and molecules to be placed in position by a 

 Power external to themselves. The same hypothesis is 

 open to you now. But if in the case of crystals you have 

 rejected this notion of an external architect, I think 

 you are bound to reject it in the case of the grain, and 

 to conclude that the molecules of the corn, also, are 

 posited by the forces with which they act upon each 



