PBODUCTION AND UTILIZATION OF FATS AND OILS 31 
The genera} use of cod-liver oil in the treatment of malnutrition 
and associated diseases is comparatively recent, although cod livers 
and the oil from them have been used for centuries as a medicine. 
At one time the low-grade, dark oil was believed to be more valu- 
able than the light-colored oil obtained from fresh livers. The light - 
colored oil is now considered better. 
Low-quality cod-liver oils are employed chiefly by the leather 
industry. 
' The oil extracted from the livers of various species of dogfish, 
sharks, and rays is used chiefly for technical purposes. The extrac- 
tion of shark-liver oil, practiced for a long time in the Orient, par- 
ticularly on the coasts of Japan, has recently become an established 
industry at several places on the Atlantic seaboard of the United 
States, 
WAXES 
BEESWAX 
The worker bees secret beeswax, which constitutes the honeycomb. 
The color of the crude beeswax ranges from light yellow to orange 
red. 
Most of the methods for rendering the wax are based on melting 
it and either allowing the impurities to settle or removing them by 
filtration. Large producers grade the combs before they render the 
wax, separating those of better quality from the older and discolored 
combs. The modern commercial method consists of melting the 
comb freed from honey, removing the larger impurities, and press- 
ing the molten wax in a warm press. The residue is heated and 
pressed once or twice more in order to obtain as much of the wax 
as possible. Small producers boil the wax with water and allow the 
mixture to stand until the impurities have settled and the wax has 
risen to the surface. The wax may be skimmed off at once or allowed 
to solidify, in which state it can be more completely removed. When 
necessary the treatment with boiling water is repeated once or several 
times to further purify the wax. The wax obtained by any of these 
methods constitutes the yellow beeswax of commerce. 
Crude beeswax varies in character and composition with the race 
of the bees, the variety of pollen which they consume, and the care 
used in preparation. The lighter-colored waxes, which may be 
readily bleached, are more valuable than darker-colored waxes. 
Crude beeswax of good quality has a sweet characteristic odor, is 
brittle when cold, and exhibits on fracture a coarse granular struc- 
ture. Bleached wax is more brittle than the unbleached and shows a 
smooth, nongranular fracture. 
Beeswax is bleached either by exposing it in the form of thin rib- 
bons to moisture and sunlight or by treating it with ozone, hydrogen 
peroxide, or other chemical bleaching agent. The satisfactory chemi- 
cal bleaching of the wax requires suitable equipment and much expe- 
rience. Beeswax from some sources can never be more than partially 
bleached. Bleached wax of good quality is either white or very light 
yellow. 
Beeswax is used chiefly in making polishes, modeling wax, and 
candles. Smaller quantities are used in pharmaceutical preparations, 
for treating leathers, and for waterproofing. 
