THE CAUSATION OF DISEASE. 5 



that there is only one exception to this law which has 

 been advanced with any cogency — viz., the Power of the 

 Will. It is argued by the supporters of the Freedom of the 

 WW, that this faculty may act differently under exactly the 

 same circumstances — that is to say, the motives to action 

 remaining the same (both in respect of quality and quantity), 

 the Will, unfettered by any rigid principle of cause and 

 effect, is free, by a power peculiarly its own, to determine 

 action in any given direction. It is probable, however, that the 

 will forms no exception to the Law of Causation. 



Since, then, every effect can be referred to material con- 

 ditions, it follows that in studying the causes of disease our 

 search must be directed into the material conditions out of 

 which disease arises. 



