810 



FOODS AND FOOD ADULTERANTS. 



acter. A number of experiments are adduced to prove this position. A sample of 

 pure Alsatian flower honey was dissolved in twice its weight of water. The solution 

 polarized 28. It was then subjected to dialysis for sixteen hours, after which the 

 residue in the dialyzer was optically inactive ( 0). Thirty grams of a pure honey 

 were dissolved in 150 grams of water, the solution decolorized and then dialyzed. 

 After eighteen hours the residue was inactive. Fifty grams of a similar honey were 

 dissolved in 250 grams of water. After sixteen hours' dialysis the residue was opti- 

 cally inactive. On further evaporating this residue and again dialyzing its inactivity 

 remained unaltered. A 10 per cent solution of glucose sirup, which polarized 100, 

 was decolorized and dialyzed. After sixteen hours it still polarized 5. The residue 

 was then concentrated, and in proportion as this progressed so rose the angle of polar- 

 ization. Forty grams of a pure honey, polarizing in a 1 in 2 solution, 35, were mixed 

 with 10 grams of glucose sirup. A 10 per cent solution of this mixture was subjected 

 to dialysis, and the residue was found to remain dextrogyrate at 4. Thirty grams 

 of a pure honey were mixed with 20 grams of glucose sirup dissolved in 250 parts of 

 water and the solution decolorized by charcoal. It polarized -f- 65. After twenty- 

 four hours' dialysis the residue retained a permanent polarization of 14 -J-. After con- 

 centrating this residue to half its weight its polarizing angle had increased to 60. 

 Fifty grams of a glucose honey were dissolved in 250 grams of water. The solution 

 polarized -{- 95. It was then dialyzed and the liquid on the dialyzer examined at in- 

 tervals of two hours. 

 It polarized after 



2 hours 45 



4hours 33 



6 hours 18 



b hours . . .15 



9hours 12 



10 hours 11 



11 hours 10 



12 hours .. .10 



Further dialysis did not change the angle (10). 



General conclusion : Any honey which, after having been dialyzed, does not polar- 

 ize to the right, is free from glucose. Any honey retaining a dextrogyration after 

 this treatment is adulterated with glucose. 



EXAMINATION OF HONEY.* 



Dr. Mansfeld made the statement that the greater part of commercial honey was 

 adulterated, and that there was no short yet reliable method known for the examina- 

 tion of honey. The methods of Haenle and Dieterich can not be recommended. 

 The best results are given by inversion and by fermentation with compressed yeast. 

 Not beer or wine yeast. The optical examination is very reliable. 



CRYSTALLOIDS AND COLLOIDS OF HONEY.t 



For diffusion of honey, a parchment paper tube of 25 mm diameter is used. This 

 is filled with a solution of honey in three times its weight of water and hung in U 

 form in a beaker of water. In Dieterich's experiments diffusion was carried on for 

 seventy-two hours, at an average temperature of 17. At the expiration of this time 

 the surrounding water became colored a pale yellow, and on evaporation gave a sirup 

 amounting to 50 per cent of the honey employed. This sirup could not be brought 

 to crystallize, despite repeated solutions in alcohol. Flavor and odor were extra- 

 ordinarily good ; better, indeed, than those of any other honey Dieterich had over 

 handled. The fluid remaining in the tube contained slimy flocks, although the orig- 

 inal honey solution had been filtered. After evaporation the residue possessed no 

 odor of honey whatever. The taste was feebly sweet. 



'Versammlung Nahrungsmittel Chemiker u. Mikroskopiker, Vienna, Oct. 13, 1891. 

 tE. Dieterich, Chem. Centralblatt, 1877, 318. 



