X PREFACE. 



towards the parts where its constituents acquire 

 vital properties, these two fundamental pheno- 

 mena of organic life cannot be explained by a 

 simple law of mixture. 



The Experiments described in the following pages 

 will, perhaps, be found to justify the conviction that 

 these organic movements depend on the transpira- 

 tion and on the atmospheric pressure. 



The importance of the transpiration for the 

 normal vital process has indeed been acknowledged 

 by physicians ever since Medicine had an existence ; 

 but the law of the dependance of the state of health 

 on the quality of the atmosphere, on its barometric 

 pressure, and its hygrometric condition, has been 

 hitherto but little investigated. 



By the researches contained in my examination 

 of the constituents of the juice of flesh, as well as 

 by those described in the present work, the com- 

 pletion of the second part of my Animal Chemistry 

 has been delayed ; but I did not consider myself 

 justified in continuing that work until I had ex- 

 amined the questions suggested by, and connected 

 with, those researches. 



DR. JUSTUS LIEBIG. 



GIESSEN, February , 1848. 



