LAWS OF PHYSICAL FORCE. 323 



The affinities and repulsions of the component parts of 

 matter, by which its mutations are effected, constitute the 

 chemical forces. These forces are of varying and complex 

 intensities, and are still but vaguely understood even by 

 our most able practical chemists ; yet the reality of such 

 forces is extensively evidenced to our senses, though they 

 are seldom such as can be distinctly measured like the me- 

 chanical forces. 



With respect to the vital forces, they are of a still more 

 complex and recondite nature, and we must be content in 

 our present state of knowledge to place these forces among 

 the many other sublime and mysterious laws impressed 

 upon organic matter by an all-wise Providence, and which 

 are not yet placed within the range of man's mental vision. 

 We simply know that the vital forces are, in part, controlled 

 by the will, and a greater portion of them are called into 

 action by organic stimulants ; and since both kinds of action 

 cease with death, they are properly treated as vital forces. 

 Whilst we know not how the vital forces control the me- 

 chanical and chemical forces exerted in and by living beings, 

 there is no lack of proof that they do in fact command the 

 other forces exerted through organic nature. 



I shall here cite an eloquent passage from an essay 

 (given in a popular journal, ^ Once a Week,' for i3tli 

 October, 1865) by one of the most able exponents of what 

 is called the ^^ New Philosophy,'' as follows, namely : — 

 ^^ The great philosophical doctrine of the present era of 

 science, as the conservation of energy has been worthily 

 styled, teaches us that the activity which we see manifested 

 in all the natural forces is a constant quantity, or, in other 

 words, that there is a definite amount of force distributed 

 through nature, which is invariable in amount, and which 

 we can neither add to nor take from, but whilst the force 

 in one form disappears it reappears in another form. But 

 what do we mean by the term force ? The simplest defini- 



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