422 CHEMICAL DISCOVERY AND INVENTION 



has been called acrose, and was one of the first produced syn- 

 thetically by Fischer. Acrolein and its dibromide have long 

 been known ; by treating the latter with baryta a condensation 

 of two molecules into one is brought about, the bromine being 

 eliminated ; 2C 3 H 4 OBr 2 +2Ba(OH) 2 =C 6 H 12 6 +2BaBr 2 . 



From the sugar thus produced others can be obtained as the 

 result of internal changes brought about by methods of which 

 the general nature has already been indicated, a Acrose appears 

 to be identical with inactive fructose. 



To build up a higher saccharose from one containing a smaller 

 number of atoms of carbon a well-known method has been made 

 use of which consists in adding on the elements of hydrogen 

 cyanide to the lower sugar and then splitting off the nitrogen 

 from the resulting compound. Thus glucose C 6 H 12 6 may be 

 made to yield by a series of steps the heptose or glucoheptose 

 C,H 14 7 . 



On the other hand, glucose may be deprived of one atom of 

 carbon and the chain shortened down to five atoms by a series 

 of operations which have a certain relation to the above. 



By the action of hydroxylamine glucose, like other aldehydic 

 compounds, yields a substance called an oxime, and from this 

 the elements of water may be removed. By further operations 

 the elements of hydrogen cyanide are eliminated. The principal 

 stages are shown below : 



CH 2 OH CH 2 -OH CH 2 -OH CH 2 -OH 



I I I 



(CH-OH) 3 (CH-OH) 3 (CH-OH) 3 (CH-OH) 3 



I I I 



CH-OH CH-OH CH-OH CHO 



I I I 



CHO CH:NOH CN 



Glucose Glucose oxime Gluco-nitril Arabinose 



By such means then the monosaccharose group has been 

 extended so as to include members containing from two to nine 

 atoms of carbon with constitutional differences corresponding 

 to the glucose or aldehydic type and the fructose or ketonic 

 type. The actual number of individuals recognised and char- 

 acterised is, however, very much larger than might be inferred 

 from such a simple statement. To realise the great extent and 



