6 PRINCIPLES OF PHYSIOLOGY. 



co-operation of the auimal forces, in actions wliich they attempt 

 to explain mechanically; or, when they think that that which 

 cannot be explained mechanically, must necessarily be attributed 

 to mind; or when they would elucidate the animal motive 

 forces by the laws of natural philosophy and mechanics, and 

 never know how to determine the forces, laws, and connection, 

 by and through which the moving springs of animal life, so 

 totally different, regulate the wonderful machines of the living 

 organism. 



This defect in Physiology becomes continually the more ap- 

 parent, now that inquiry has commenced into the diseases 

 of the proper animal forces and their cure ; and the present 

 appears to be the proper time to supply it by carefully con- 

 sidering proper animal nature in its uncomplicated state, and 

 distinctly deducing the laws by which the animal forces, as 

 such, act in animal organisms. The pathology of the mind, 

 or of the nervous system, and of other diseases of the animal 

 forces, ought to demonstrate to us the deviations of the animal 

 forces from their proper laws ; but what can be really expected 

 from pathology so long as we have no distinct idea of those 

 laws, and are even ignorant of the animal forces themselves ? 

 This knowledge will never be rendered in any degree perfect, 

 if the operations of the proper animal forces are not considered 

 quite separately and by themselves, and the laws studied by 

 which they ensue in animal organisms independently of the 

 physical and mechanical forces in operation at the same time. 



From these considerations originated my idea of a physiology 

 of the proper animal nature of animal organisms, of which the 

 present work supplies the first principles, and by which the phy- 

 siology of the whole animal economy, which hitherto has been 

 extremely deficient in these principles, may for the future be 

 corrected, completed, and extended. Although I do not overlook 

 the imperfection of my own plan, and have never considered it 

 to be so well carried out, as to be satisfied with my performance, 

 still I thought it deserved to be made public even in its imper- 

 fect state ; since it would, for the first time, make known the 

 utility and necessity of separating the proper animal physiology 

 from the general physiology of the entire animal economy ; of 

 which hitherto no one seems to have ever thought. If I am 

 not deceived in my expectations, some better student of animal 



