164 W. M. HAMLET. 



ON THE CONSTITUTION OF THE SUGAR SERIES. 

 By W. M. Hamlet, f.c.s., f.i.c., Government Analyst. 



[Bead before the Royal Society of N.S. Wales, November 4, 1891.'] 



The structure of the sugar molecule, so long enveloped in the 

 obscurity of an empirical formula was first investigated by Fittig 

 and Baeyer, who, reasoning upon the well-known reducing action 

 of dextrose compared with the similar action of aldehyde, came 

 to the conclusion that dextrose contained either an aldehyde or 

 ketone nucleus. That such a conclusion was the right one was 

 afterwards proved by Kiliani in the preparation of the ammonia 

 salt of hexahydroxyheptoic acid. 



The splendid synthetic researches of Fischer and Tafel, and of 

 Tollens with reference to the carbohydrates have placed our know- 

 ledge of the sugars upon a much higher level, the entire group 

 may now be regarded as a definite homologous series like the 

 alcohols and hydrocarbons. There is no further need for me to 

 refer to these researches, the object of this paper being to apply 

 a ring formula to the various members of the sugar family. 



The value of hypothesis is nowhere better exemplified than in 

 the famous benzene ring of Kekule of which it has been said, on 

 the occasion of the twenty-fifth anniversary of the promulgation of 

 Kekule's theory of the constitution of the aromatic compounds : — 

 " This theory found the chemistry of even the immediate deriva- 

 tives of benzene an almost unfilled field : it has transformed it 

 into a fertile province, to which have been annexed regions the 

 very existence of which was unknown." The unequivocal success 

 of this method of representing the constitution of organic com- 

 pounds leads me to think it may be serviceable in the study of 

 the sugars. , 



Starting with the geometrical formula for formic aldehyde we 

 have — 



