THE CAUSATION OF DISEASE. 219 



namely, in causing some to rise and others to sink in the social 

 scale. In all the ordinary affairs of life, we find the principle 

 of a the survival of the fittest "' in full play, and I cannot here 

 refrain from extending my observations on this head, although, 

 by so doing, I shall be travelling somewhat beyond the scope of 

 this work. 



Just as the physical self and the physical E coming into 

 contact, act and react upon one another, so also do the 

 mental self and the mental E. The latter pair work of 

 course in a physical medium, for mind is inseverably con- 

 nected with matter, and the mental E operates by impres- 

 sing the organs of sense through a physical medium. Now 

 the mental success — that is to say, the intellectual or moral 

 success — of any individual is the outcome of the mutual inter- 

 action of the mental self and the mental E, just as the success 

 of an individual, from a physical point of view, is the out- 

 come of the inter-action of the physical self and the physical 

 E. A man's success or failure in life is not a matter of 

 chance, but the outcome of fixed and immutable law. The 

 more we study the career of any individual the more we shall 

 be struck with this fact. If we observe a rival outstripping 

 us in the race of life, we are sometimes apt to attribute his 

 greater success to greater luck, or, in more scientific terms, to 

 a more favourable mental E ; and we are the more disposed to 

 do so, if We have ourselves achieved but a small measure 

 of success. But if we closely scrutinize the character of 

 our rival, we shall find in him all the elements of success, 

 intellectual and moral qualities which we ourselves do not 

 possess. These qualities, individually, may appear insignificant, 

 but collectively, they make up a force which surely, steadily, 

 irresistibly, wins the goal. Whether a man achieve a proud 

 position in life, or whether he prove an abject failure, we may 

 safely assert that his success or failure is the logical and 

 inevitable result of the mutual inter-action of his mental self 

 and mental E, and that that result might be calculated with 

 as much mathematical exactness as any purely mechanical 

 problem in physics, did we possess the necessary insight. 



The part played by the E in the result is no doubt im- 

 portant, but we must not overrate it. " Some men," says 



