132 TRANSACTIONS OF THE 
Physics no longer deals as of old with mechanics, 
sound, heat, light, magnetism, and electricity, as with 
distinct and unrelated sets of facts. Even chemical and 
astronomical facts are now dealt with in physics. This 
restoration of a broken unity by physics has, no doubt, 
been largely due to the discovery of the electron, a unit 
upon which all physical facts are seen to depend. But 
biological, psychological, and sociological facts are never 
found dissociated from matter. They also are physical 
facts. 
_ As the psychical nature of all energy complexes 
becomes more fully understood, and as these psychical 
realities become properly correlated with the strivings 
and achieved habits of men, there will be furnished 
a unit in terms of which all the heretofore sundered facts 
of human experience can be understood; and the unity of 
material nature, broken for us because of the piece-meal 
way in which the study of it has been approached his- 
torically, will be full appreciated. 
