FOODS 111 



Honey consists of the saccharine substance collected by 

 bees from the nectaries of flowers, and deposited in the cells 

 of the honeycomb. Honeydew is a secretion of the leaves 

 of various trees and plants, and is also gathered by bees. 



Honey contains dextrose and laevulose, and hence, like 

 invert sugar, is laevo-rotatory from 4 to 15, and the 

 reading is not altered to any extent by inversion, showing 

 the absence of cane sugar. If the reading is +, it indicates 

 the presence of glucose or cane sugar, and if after inversion 

 it is still +, then the substance is glucose. If the reading 

 is + and very high (above 100), the presence of glucose 

 is almost certain, and in this case if no cane sugar is 

 present at the same time, inversion will not change the 

 reading. Cane sugar is stated to be present in natural 

 honey at times, up to 8 to 10 per cent, and so a reading 

 of + 2 may be passed. 



Honey is largely adulterated with glucose, starch paste, 

 malt extract, and cane sugar, and imitated by adding a piece 

 of genuine honeycomb to a jar of glucose syrup. On micro- 

 scopical examination, genuine honey will always show the 

 presence of pollen grains, which would generally be absent 

 from a filtered honey. (Mel depuratum B.P. is the honey 

 of commerce melted in a water-bath, and strained while hot 

 through flannel previously moistened with warm water.) 



Beeswax melts at about 64 C. (147 F.) and is carbonized 

 by strong sulphuric acid on boiling ; paraffin wax melts at 

 54 to 57 C. (130 to 135 F.) and is not carbonized on 

 boiling with strong sulphuric acid. 



Analysis. Water varies from 15 per cent to 25 per cent, 

 and is estimated by dissolving 5 grm. in water, making 

 up to 100 c.c, and drying 10 c.c. mixed with 10 grm. of 

 sand at 96 C. until weight constant. Ash. Ignite 2 to 5 

 grm. at a low heat. Varies from o-i to 0-3 per cent, 

 and is alkaline. If more, it suggests glucose ; test for 

 CaS0 4 , and neutrality. 



Polariscope Reading. Dissolve the " normal weight " of 

 honey in water and make up to 100 c.c, filter through a 

 small quantity of bone charcoal to clarify, and examine in 

 saccharimeter. 



Glucose. Syrup ; sticky precipitate with one part of 

 water and ten of methyl alcohol. 



