THE STRUGGLE FOR LIFE. 225 
For there is as true a correlation between the different organs 
of the body, and between the different faculties of the mind, 
as has been proved to exist between the various forms of 
the physical forces of Nature. It is a well-known fact 
that it is possible to convert all the physical forces one 
into another, and moreover, their exact equivalents in terms 
of each other have been determined. Now no dividing line 
can be drawn between the purely physical and the vital 
forces, since the life of the cell can not only be changed into 
the motion of a limb and the production of heat, but also 
into the process of thought: the chemical combinations of 
our food may, therefore, be called the physical basis of the 
mind. Nature is one and indivisable, and governs all 
bodies, both of the organic and inorganic worlds, and all 
the forces of Nature are linked together under a ‘ Reign 
of Law.” 
BSE De 
