X PREFACE. 



had attained its highest perfection, but came into 

 action with each new observation. 



All existing experience and observation in other 

 departments of science reacted, in like manner, on 

 the improvement and developement of chemistry ; 

 so that chemistry received from metallurgy and 

 from other industrial arts as much benefit as she 

 had conferred on them. While they simultaneously 

 increased in wealth, they mutually contributed to 

 the developement of each other. 



After mineral chemistry had gradually attained 

 its present state of developement, the labours of 

 chemists took a new direction. From the study 

 of the constituent parts of vegetables and animals, 

 new and altered views have arisen ; and the present 

 work is an attempt to apply these views to physio- 

 logy and pathology. 



In earlier times the attempt has been made, and 

 often with great success, to apply to the objects of 

 the medical art the views derived from an acquaint- 

 ance with chemical observations. Indeed, the great 

 physicians, who lived towards the end of the seven- 

 teenth century, were the founders of chemistry, and 

 in those days the only philosophers acquainted with 

 it. The phlogistic system was the dawn of a new 

 day; it was the victory of philosophy over the 

 rudest empiricism. 



