380 PROCEEDINGS OF THE OHIO ACADEMY OF SCIENCE. 



knowledge of this important group — although sucrose itself 

 has not been synthesized and the constitution of the starch 

 molecule still remains a mystery. Later Fischer began the study 

 of that group of compounds found in the living organism which 

 includes such substances as uric acid, caffeine, theobromine, 

 xanthine, and hypoxanthine and showed that all of these may 

 be considered as derivatives of one parent substance to which 

 he gave the name purine. 



More recently Fischer began work upon that highly complex 

 series of compounds known as the proteins, which form the basic 

 material of the living cell. His results in this field are of so 

 much importance that a brief resume of them must be included 

 in any discussion of recent advances in chemistry. 



At present some 40 or 50 natural proteins have been isolated 

 and their properties studied. Their composition is wonderfully 

 complex. It is possible to decompose these complex molecules, 

 or in chemical terms to hydrolyze them into a number of simpler 

 molecules. The resulting products belong to the class of com- 

 pounds known as the amino acids of which 17 have been isolated 

 and studied. These acids may be regarded as the building stones 

 out of which the protein molecule is constructed. After making 

 an extensive study of these amino acids Fischer began the work 

 of re-combining these parts of the i)rotein molecule in an effort 

 to build up the original molecule. In this way he succeeded in 

 building up more than 200 comj^ounds, the most complex one 

 having a molecular weight of 12 13. The compounds obtained 

 in this synthetic process have the general properties of proteins 

 but even the most complex molecule synthesized is still far short 

 of the molecules of natural proteins, the molecular weights of 

 which lie probably around 5000. While some progress is being 

 made in this field of investigation, nevertheless, the task of 

 building up a molecule identical with that of any definite natural 

 protein, would seem to be almost insuperable ; for the molecule 

 must be formed by the union of a very large number of amino 

 acid residues. These residues may combine, however, in perhaps 

 hundreds of different ways and if we are to synthesize any nat- 

 ural protein then this combination must take place in only one of 



