44 EIGHTH REPORT 1838. 



of sugar of grapes is stated by Prout at 1*5. Diabetic sugar dissolves 

 without limit in boiling water, and at 62° in its owq bulk of water. 



By analysis with oxide of copper, the constitution of this sugar was 

 found to be 



Carbon 37-23 or 12 atoms = 9-00 or per cent. 38-09 



Hydrogen.... 7*07 13 .. 1*625 .. 6-88 



Oxygen 55-70 13 . . 13 .. 55-03 • 



100-00 23-625 100-00 



Starch sugar, according to Dr. Prout, is composed of 



Carbon 12 atoms 9- 



Hydrogen.... 14 .. 1*75 

 Oxygen 14 . . 14-0 



24-75 

 differing from diabetic sugar by an additional atom of water. 



Pure crystallized sugar, according to the analysis of Liebig in 1834, 

 is composed of 



Carbon 12 atoms 9- 



Hydrogen .... 1 1 . . 1 "375 



Oxygen 11 11- 



21-375 



By uniting the diabetic sugar with oxide of lead, it was found to 

 have combined with three atoms of oxide of lead, and to have lost three 

 atoms of water, constituting a trisaccharate of lead, composed of 



Carbon .... 12 atoms = 9- 

 Hydrogen.. 10 .. = 1-25 

 Oxygen 10 .. =10- 



20-25 

 Oxide of lead 3 . . = 42-00 



In this combination the diabetic sugar is therefore exactly isomeric 

 with common sugar, in its combination with two atoms of oxide of lead, 

 as determined by Berzelius. 



From the yellowish-brown solution which had yielded the trisaccha- 

 rate of lead the addition of alcohol caused a Hocky precipitate to fall, 

 which appeared, on analysis of a saiidl quantity, to be disaccharate of 

 lead, containing 



Sugar 0-56"| 



Oxide of lead. . ^0^ Lrnearlytwo atoms of lead to one of sugar; 

 l-2oJ 



and Dr. Thomson supposes from some trials he made that the sugar in 

 this combination had lost two atoms of Mater, so as to be composed of 



