AQUATIC PRODUCTS IN ARTS AND INDUSTRIES. 



225 



extract of beef, it is removed from the vacuum pan, assayed for 

 alkaloidal contents, and then dissolved in wine in pi-oper proportion 

 to represent the "active principles" contained in one-fourth its bulk 

 of cod-liver oil. 



Onl}^ about 10 per cent of the cod-liver oil consumed in this country 

 is produced in the American fisheries, the great bulk of it being 

 imported from Norway. As already shown, the product of medicinal 

 oil in the United States fisheries is onl}^ about 25,000 gallons each 

 year, whereas the imports usually exceed 200,000 gallons annually, 

 and in some years exceed 500,000 gallons. 



The following summary, showing the total quantity and value of 

 cod-liver oil imported for consumption into the United States during 

 a series of years, is compiled from the United States customs returns : 



Statement of the quantity and value of cod-liver oil imported into the United 

 States during a series of years. 



PREPARATION OF COD OIL FOR TECHNICAL PURPOSES. 



The methods of extracting cod oil for currying and other technical 

 purposes does not differ essentially from the extraction of medicinal 

 oil, the principal difference being the use of all livers secured, the 

 absence of extreme cleanliness, and the greater putrefaction or the 

 more extensive cooking of the material. Considerable common oil is 

 also expressed from the livers cooked for medicinal oil after the latter 

 has been dii)ped or skimmed off. 



The original method of extracting cod oil, and the most common one 

 at the present time, is by putrefaction. In the Gi"and and the West- 

 ern banks fisheries, during the process of dressing the fish, the livers 

 are collected and placed in liver-butts. These butts are characteristic 

 of vessels engaged in a salt-fish trip; in the market fishery for cod, 

 haddock, etc., their place is taken by upright barrels or guriy kids. 

 There are two liver-butts on each vessel; they consist of large casks, 

 with a cajDacity for about 150 gallons each, mounted horizontally on 

 skids immediately in front of the house and lashed securely to the 

 deck. On the top, in the bilge of each cask, there is a large square 

 opening, covered with a piece of tarpaulin securely fastened at one 



F. C. 1902 15 



