ON PHYSICO-CHEMICAL METHODS AND PROBLEMS, n 



back to the very foundations of modern chemistry in 

 order to obtain a conception of its applicability to biological 

 questions. In what follows an attempt will be made 

 to ascertain the value of physico-chemical methods in 

 special questions in medicine. A division of our sub- 

 ject might follow either one of two schemes. According 

 to the first the division would follow that current in 

 physical chemistry. A second, however, which seems 

 better adapted to our purposes, takes into consideration 

 the medical problems that have made use of the new 

 methods. 



We can readily distinguish between two fields of 

 biochemical research. One in which dead material is 

 studied and through a discovery .of the structure of 

 chemical substances, such as the proteins and carbo- 

 hydrates, an explanation of their biological significance 

 is sought; and a second which approaches the tissues 

 and their functions directly and endeavors to unveil 

 their secret vital activity through an investigation of 

 their constituents and products. Often investigations 

 that utilize more or less strictly the living organism have 

 a knowledge of the results obtained in the first field upon 

 which to base their work. True as seems to be the 

 assertion that a broad chasm exists between the great 

 group of proteins and living protoplasm, equally true 

 is it that a bridge leads across this chasm, even though 

 investigation has not yet succeeded in recognizing the 

 nature of this connection. We may therefore expect that 

 in the chemical and physical reactions of the proteins 

 there exist even now many of the elements of physiological 

 and pathological reactions. In fact this expectation 

 has been fulfilled in great measure more especially 



