220 THE WEALTH OF THE SEA 



Cod-liver oil and other fish-liver oils owe their 

 therapeutic value to their fat-soluble vitamine con- 

 tent. These liver oils are high both in the antixeroph- 

 thalmic, growth-promoting vitamine A, and the 

 anti-rachitic vitamine D. Cod-liver oil is especially 

 valuable in the nutrition of children, since it aids in 

 the proper growth of bones, thus preventing rickets. 

 Furthermore it stimulates growth because of its con- 

 tent of the growth-promoting vitamine. Cod-liver and 

 other fish-liver oils are also used in the treatment 

 of all forms of malnutrition, various forms of tuber- 

 culosis, chronic rheumatism, and gout. Cod oil, or 

 the technical grade of cod-liver oil, finds extensive 

 use in the manufacture of "chamois" leather, in the 

 currying (finishing) of all leathers, and in the man- 

 ufacture of oiled cloth and low-grade soaps. 



Commercial cod-liver oil and cod oil are seldom 

 made from cod livers alone. Inasmuch as the oils 

 obtained from the livers of the haddock, hake, pol- 

 lack, and cusk can scarcely be distinguished from 

 cod-liver oil, and since these fish are caught on the 

 same grounds, the livers are seldom kept separate. 

 Thus commercial medicinal cod-liver oil is really a 

 mixture of several liver oils. Two other liver oils, 

 those from the shark and skate, are of commercial 

 importance, finding use in the finishing of leather. 

 Some shark-liver oil is now manufactured in America 

 in connection with the shark leather industry. Most 

 of it, however, comes from the Orient, where shark 

 meat and fins are valued highly for use as food. The 

 Japanese produce large quantities of shark-liver 

 oil from many different species of sharks. Liver oils 



