( 564 ) 



temperature, I waited until most of the hydrogen bromide had been 

 evolved and the reaction was consequently nearly over. The excess 

 of acetyl bromide was then distilled in a high vacuum and the 

 iwoduct, consisting of a tenaceous, yellow mass, treated with iced 

 water, then dissolved in alcohol and placed in a desiccator containing 

 caustic potash and kept at a low temperature. A crystallised mass 

 was obtained which after being submitted to pressure was recrystal- 

 lised at a low temperature when beautiful crystals, free from bromine, 

 were deposited. 



These crystals are colourless, odourless, taste bitter and melt at 

 131° — 132°. In a high vacuum they may be sublimed even at 95° 

 more rapidly at 105°; the sublimate has the same melting point. 



The ultimate analyses gave a mean result of C 48.267o, H 5.867o- 



The molecular weight determination by the lowering of the freezing 

 point of benzene gave a mean of 355. 



The acetyl determination was carried out by saponification with 

 n/io sodium hydroxide at a low temperature. Blank experiments 

 made under similar conditions showed that fructose is not altered 

 or converted into acids. The saponification was nearly complete after 

 two hours and quite so in 18 hours; after 28 hours no sensible 

 decomposition of the fructose had set in and about the same figures 

 were obtained as those in 18 hours. The average amount of acetic 

 acid found was 69.42 7„. 



It is, therefore, a fructose tetracetate Ci^H^oOio for which theory 

 requires C. 48.25''/(, H. 5.867o, molecular weight 348 acetic acid 

 68.96V„. 



This compound is but little soluble in water, ether, benzene and 

 ligroin, readily so in alcohol and chloroform. 



The chloroform solution was used to determine the rotatory power. 

 It polarises to the left and the specific rotation of d. fructose tetra- 

 cetate at 20° was found [«po — 91°.38. 



D 



Dr. F. M. Jaeger was kind enough to investigate the crystals and 

 reported as follows : 



d. Fructose tetracetate (Brauns). 



Ci,H,„0,„; Melting point 132° C. 



Sp. Gr. of the crystals at 15° = 1.388; Mol. Vol. = 250.72. 



From ethyl alcohol -|- ether, it is obtained on slow evaporation, 

 in beautiful, colourless, shining little crystals which may be readily 

 measured and which possess a pure geometrical structure. 



The compound is Jiemimorphous ; its symmetry is that of the 

 monoclino-sphenoidic class. It, therefore, does not possess a single 



