PRESIDENTS ADDRESS. XV 



It is to the work of Kiliani and especially to that of Emil Fischer 

 that Chemistry is indebted for the solution of these problems. 

 In 1866 Kiliani succeeded in determining the constitntion of both 

 glucose and fructose; and within the following four years Fischer 

 not only synthesized both glucose and fructose, but also a large 

 number of other related sugars previously unknown, and succeeded 

 in completely clearing up the Chemistry of the whole group of 

 saccharoses. Fischer's brilliant work was made possible by his 

 discovery of a means of effecting what had baffled earlier chemists, 

 the isolation of a sugar in pure condition from a mixture. The 

 key to this problem he found in the reagent, phenylhydrazine, 

 which he discovered would convert a sugar into an easily purified, 

 easily identified, insoluble compound. But it requires a magician 

 to wield a magician's wand : and phenylhydrazine in the hands 

 of any less gifted worker would not have accomplished what it did 

 in the hands of Emil Fischer. When after a few years work he 

 finished his investigation of the monosaccharoses, that chapter of 

 Chemistry was left practically complete. 



The syntheses in the group of disiccharoses have been much 

 less numerous. The most notable has been that of cane sugar, 

 and with a passing reference to the way in which this has been 

 accomplished we shall leave the sugar "-roup. 



When cane sugar undergoes inversion it takes up the elements 

 of water and yields equal quantities of glucose and fnictose. 

 This and other reactions indicate that cane sugar is some sort of 

 compound of glucose and fructose with water eliminated. The 

 glory of first succeeding in producing such a compound is due to 

 Marchlewski, who obtained cane sugar by the reaction of aceto- 

 chlorogluoose on potassium fructosate in 1899. 



When we turn to the protein group we have to deal with the 

 most complex substances known to Chemistry. At the same time 

 their relation to the living organism makes them physiologically 

 the most important of all substances. 



The difficulty of research in this branch of organic chemistry 

 are enormous. Many members of the group are non-crystalline 

 substances, and hence excessively difficult, or impossible, to 

 obtain in pure condition. Again they are, as a rule, very sensitive 



