FISH MEAL AND OIL 



489 



Thus, X is the percentage of octobromide, tj the percentage of hexabromide, and 

 B the percentage of bromine in the ether insoluble bromides. 



Since fish, fish-liver, seal, whale, and sperm oils are the only oils known to 

 contain large amounts of the glycerides of clupanodonic or other highly un- 

 saturated acids capable of forming octobromides, this test may be used to dis- 

 tinguish between marine animal oils and vegetable drying oils. 



Fish oils when treated with nitrous acid, as in the elaidin test, yield either a 

 liquid product or a pasty or buttery mass separating from the fluid portion. Non- 

 drying oils yield solid hard masses when treated with nitrous acid. 



Old marine animal oils and those bleached by sunlight yield dark brown soaps 

 upon hydrolysis with alkalies, whereas the freshly prepared oils give slightly 

 colored soaps. 



Menhaden Oil. The production of menhaden oil as shown in Table 103 far 

 exceeds that of any other fish body oil. 



Composition. The maximum and minimum constants for menhaden oil that have 

 been published are given below: 



Specific gravity at 59° F (15° C) 



Solidifying point ° F 



Saponification value (mg. KOH) 



N 

 Reichert value ( cc — KOH ) 

 10 



Iodine value (per cent) 



Maumene test ° F 



Specific temperature reaction 



Butyro refractometer 104° F (40° C) 



Unsaponifiable matter (per cent) 



253.4-262.4= 



0.9284-0.9311 



24.8 (-4°C) 



188.7-193.0 



1.1 



147.9-192.9 



(123-128° C) 



306 



71.3-72.0° 



0.61-1.60 



The high saponification value, the small amount of unsaponifiable matter, and 

 the high proportion of glycerol yielded upon saponification show that menhaden 

 oil consists almost entirely of glycerides. 



The composition of the fatty acids of menhaden oil has been determined by 

 observing the lowering of the melting point by the addition of pure fatty acids. 

 This indicates the following composition: 



Palmitic acid 22.7 



Myristic acid 9.2 



Stearic acid 1.8 



Unsaturated acids with 16 carbon atoms None 



" 18 " " 24.9 



" 20 " " 22.2 



" 22 " " 20.2 



The unsaponifiable matter consists chiefly of cholesterol, which causes the slight 

 optical activity of this oil. 



Use. Much menhaden oil is hydrogenated and used for the manufacture of 

 soaps. When properly hydrogenated a sohd, odorless, almost colorless fat is pro- 

 duced. This hardened oil is extensively used in the manufacture of laundry soap 



