General Scope of Biochemical Study. 1 1 



organic substance. The elements of which these salts are 

 composed appear to be indispensable for the life of the 

 organism, and must be administered with the food. Their 

 exact functions have not yet been ascertained, but they 

 appear markedly to influence the physical characters of the 

 tissues. The latter are composed of biological units, or 

 " cells," which function normally only when they possess a 

 certain physical structure and maintain a definite state of 

 aggregation, and there is no doubt that the inorganic salts 

 play an important role in the preservation of this state. 

 The study of problems dealing with factors of this kind is, 

 however, still in its infancy, and it is not possible to 

 discuss them in an elementary treatise of this character, 

 except in a very cursory manner. It must not be for- 

 gotten, however, that such problems exist, and that their 

 study forms an important branch of biological chemistry, 

 which is bound, in the near future, to lead to important 

 practical results. 



As bodies of living objects are made up chiefly of 

 organic substances, the main part of this book will be 

 devoted to their consideration. It is proposed, in the first 

 place, to devote a certain number of chapters to the 

 methods of examining these substances and determining 

 their structure. A short account will follow of some 

 typical methods for the investigation of metabolism, and 

 of ascertaining the normal chemical functions of individual 

 organs. 



