XXVI PREFACE. 



established ; and this influence was not delayed 

 till chemistry had attained its highest perfec- 

 tion, but came into action with each new ob- 

 servation. 



All existing experience and observation in 

 other departments of science reacted, in like 

 manner, on the improvement and development 

 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 development 

 of each other. 



After mineral chemistry had gradually attain- 

 ed its present state of development, the labors 

 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 physiology 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 acquaintance with chemical observa- 

 tions. Indeed, the great physicians, who lived 

 towards the end of the seventeenth 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 



