BY-PRODUCTS OF FISHERY INDUSTRIES 219 



New methods of refining the oil have produced 

 entirely colorless and tasteless oil, which may be 

 taken by the most sensitive persons without nausea. 

 The oil has also been hardened by treatment with 

 hydrogen and thus transformed into a colorless, odor- 

 less, solid fat resembling tallow. Indeed all of the 

 various consistencies, from a limpid oil to a mushy 

 fat, a lard-like substance to an exceedingly hard fat 

 such as stearin, may be obtained. Such solid fats 

 are suitable for increasing the fat-soluble vitamine 

 content of margarin and other vegetable fats. The 

 semisolid fats may be used for the preparation of 

 tasteless emulsions for medicinal purposes. Methods 

 of separation of the fat-soluble vitamines have been 

 discovered which have enabled chemists to obtain solid 

 vitamine concentrates that can be conveniently ad- 

 ministered in tablet form. 



Modern manufacturing processes for the produc- 

 tion of medicinal oil require the use of strictly fresh 

 cod livers. Such livers are available chiefly in cold 

 weather. For this reason medicinal cod-liver oil is 

 prepared only in late autumn, winter, and early 

 spring. The livers are carefully heated in steam- 

 jacketed kettles, after which the oil is separated from 

 the tissue by pressing under moderate pressure in 

 bag presses. Still better oil may be made by render- 

 ing the livers in vacuum boilers. This treatment pre- 

 vents overheating and thus insures a light-colored 

 oil. Some cod-liver oil factories operate a small 

 refrigeration outfit in conjunction with their plants. 

 In these factories, the room in which the livers are 

 pressed is kept cold, thus preventing decomposition. 



