II] OF THE EFFECTS OF SCALE 77 



George Johnstone Stoney, the remarkable man to whom we owe 

 the name and concept of the electron, went further than this; for 

 he supposed that molecular bombardment might be the source of 

 the life-energy of the bacteria. He conceived the swifter moving 

 molecules to dive deep into the minute body of the organism, and 

 this in turn to be able to make use of these importations of energy*. 



We draw near the end of this discussion. We found, to begin 

 with, that "scale" had a marked eifect on physical phenomena, and 

 that increase or diminution of magnitude migl^t mean a complete 

 change of statical or dynamical equiUbrium. In the end we begin 

 to see that there are discontinuities in the scale, defining phases in 

 which different forces predominate and different conditions prevail. 

 Life has a range of magnitude narrow indeed compared to that with 

 which physical science deals ; but it is wide enough to include three 

 such discrepant conditions as those in which a man, an insect and 

 a bacillus have their being and play their several roles. Man is 

 ruled by gravitation, and rests on mother earth. A water-beetle 

 finds the surface of a pool a matter of Ufe and death, a perilous 

 entanglement or an indispensable support. In a third world, 

 where the bacillus Hves, gravitation is forgotten, and the viscosity 

 of the Hquid, the resistance defined by Stokes's law, the molecular 

 shocks of the Brownian movement, doubtless also the electric 

 charges of the ionised medium, make up the physical environment 

 and have their potent and immediate influence on the organism. 

 The predominant factors are no longer those of our scale ; we have 

 come to the edge of a world of which we have no experience, and 

 where all our preconceptions must be recast. 



* Phil. Mag. April 1890. 



