AQUATIC PRODUCTS IN AKTS AND INDUSTKIES. 231 



Captain Atwood wrote in regard to tlie oil from the torpedo: 



I used to go and look for tliem for their livers — for the oil. The oil is one of the 

 best lamj) oils that I ever saw. It has been nsed sometimes beneficially in cases 

 of cramp. I got a gallon of oil from one liver. I do not know bnt I have seen a 

 cramp-fish big enough to make three gallons of oil." 



The liver of the saw-fish {Pristls), numerous on the South Atlantic 

 and Gulf coasts of the United States, yields from 6 to 18 gallons of 

 oil. It is said that in British Guiana this oil is used for illumination 

 and also for anointing the bodies of the inhabitants. The liver of 

 the elephant-fish {Chimcera), which occurs in abundance on the Cali- 

 fornia coast, is large and yields choice oil. This fish has a maximum 

 length of 2 feet and weighs 6 or 7 pounds. 



It appears from the above that the yield of oil from individual shark 

 livers ranges from much less than 1 pint in case of the dog-fish and 

 others to the 400 gallons procured from the basking shark. Other 

 than the livers, the carcasses of sharks are slightlj^ oleaginous, and 

 are rarely ever utilized in oil-rendering, but they are of course useful 

 for conversion into fertilizer. The method of extracting the oil from 

 the livers is much the same in all cases. If they are large, they should 

 first be cut in small pieces or minced, as is done with whale blubber. 

 The pieces are then subjected to heat until the cells are thoroughly 

 broken, when the oil is extracted by i^ressure or it is jiermitted to 

 drain therefrom. In case the oil is to be used for medicinal j)urposes 

 great cleanliness is observed, the livers being washed free from blood 

 and the gall bladder removed. A quantity of water is placed in the 

 kettle with the hepatic tissues and the whole boiled gently for an hour 

 or two. On cooling, the oil floats on the surface and is dipped off and 

 stored. It may be refined in precisely the same manner as cod oil. 



According to Brannt, shark oils are distinguished as being the 

 lightest of fixed oils, their specific gravities ranging from 0.870 to 

 0.880 at 59° F., so that a mixture with blubber or other fish oils can 

 at once be recognized by the higher specific gravity. They are pale 

 yellow and clear, remain fluid at 21° F.^ and contain very little stea- 

 rin. They burn with a bright flame without carbonizing the wick. 

 Brannt further states that they contain about the same constituents 

 as cod-liver oil, but are richer in iodine. On account of their per- 

 centage of gall constituents the liver oils are readily distinguished 

 from other fish oils. 



Shark oils are largely used in tanneries, in steel-tempering, and in 

 various compounds where it is desired to impart a low specific gravity. 

 They are also valuable as a body for paints for out-of-door objects, as 

 walls, fences, etc. In some localities certain kinds are used by medi- 

 cal practitioners, who consider them quite equal to cod-liver oil. In 

 the drug stores of this country shark oil is occasionally found with a 

 label suggestive of an oriental origin and recommending its use as an 

 embrocation in numerous diseases. 



a Natural History of Aquatic Animals, p. 667. 



