18 



inversion is small, while in honey adulterated with sucrose the devia- 

 tion after inversion to the left would be very great. 



On raising the temperature of the inverted solution to 87° C. the 

 polarization is far to the right, exceeding that of the algeroba honey, 

 which under such conditions polarizes but 1 or 2 degrees to the right. 

 The presence of a highly dextrorotatory substance is indicated. The 

 difference between honeydew and algeroba honey in this respect is 

 shown in the following table : 



Indirect polarization of honeydew and algeroba honey at 87° C. 

 [Readings on Schmidt and Haensch scale.] 



Sample. 



Honeydew honey. 



Algeroba honey. 



1 _ _ 



Degrees. 



+33.0 

 +36.0 

 +24.0 



Degrees. 



17 . _.. 





13 





50- ___ _ 



+2.2 

 +1.6 

 +1.2 



43 





14 









Fermentation. — Fermentation of the honey was obtained by weigh- 

 ing out 25 grams of the honey, dissolving it in water, neutralizing 

 the free acid with potassium hydrate, and acidifying with tartaric 

 acid, and adding a little potassium fluorid; 25 cubic centimeters of 

 brewer's yeast was added, the volume made up to 200 cubic centi- 

 meters, and the fermentation carried on seven days. The volume was 

 then made up to 250 cubic centimeters, clarifying with aluminum 

 cream, and filtered. Two hundred cubic centimeters was evaporated 

 to remove alcohol, and the residue made up to a volume of 100 cubic 

 centimeters. 



In these experiments the free formic acid was neutralized to pre- 

 vent its antiseptic action, but the formates so formed may also act as 

 antiseptics. 



Brewer's yeast was also used, as, according to Eaumer, G com- 

 pressed yeast completely destroys the dextrin in honey so that the 

 fermentation residue then often gives a neutral polarization. In 

 many honeys fermented by beer or wine yeast, the fermentation 

 residue causes a right-handed polarization. 



The fermentation residues of the honeydew honeys (samples 17, 

 1, and 2) under consideration, are rather strongly dextrorotatory, 

 while those of the algeroba honey (sample 11) and other floral honeys 

 are levorotatory, as shown in the table following. 



Bui. 17 



a Ztscbr. Angew. Chem., 1S90, p. 421. 



