6 VITALITY INDEPENDENT 



vegetables, without their vitality being otherwise 

 affected than by the want of a peculiar source of 

 increased energy or of disturbance. Except in 

 regard to this, all the vital chemical processes go 

 on precisely in the same way in man and in the 

 lower animals. 



The efforts of philosophers, constantly renewed, 

 to penetrate the relations of the soul to animal life, 

 have all along retarded the progress of physiology. 

 In this attempt men left the province of philoso- 

 phical research for that of fancy ; physiologists, car- 

 ried away by imagination, were far from being 

 acquainted with the laws of purely animal life. 

 None of them had a clear conception of the process 

 of developement and nutrition, or of the true 

 cause of death. They professed to explain the 

 most obscure psychological phenomena, and yet 

 they were unable to say what fever is, and in what 

 way quinine acts in curing it. 



For the purpose of investigating the laws of vital 

 motion in the animal body, only one condition, 

 namely, the knowledge of the apparatus which 

 serves for its production, was ascertained ; but the 

 substance of the organs, the changes which food 

 undergoes in the living body, its transformation 

 into portions of organs, and its re-conversion into 

 lifeless compounds, the share which the atmosphere 

 takes in the processes of vitality ; all these founda- 

 tions for future conclusions were still wanting. 



What lias the soul, what have consciousness and 



