No. 3 (1921) MANUFACTURE OF FISH OIL AND GUANO 235 



The first two A oils were so good that experiments in refinement 

 were unnecessary ; they were of the quality described as " unique " 

 in the market. The third A oil was entirely deprived of its free 

 acid by steam and alkali and in the process became very pale '; Nos. 

 4 and 5 showed similar results. 



The B oils, which were privately made oils of inferior quality 

 with many impurities, show that some improvement is possible but 

 only at great loss of oil and considerable expenditure ; the results 

 were quite incommensurate with the loss and show that really low- 

 class oil cannot be improved with commercial success. 



This table is the justification for the remarks in paragraph 132 ; 

 it is evident that the improvement by neutralization of badly 

 prepared low-class oils can hardly be a commercial proposition, 

 unless other considerations warrant it; such oils had better be 

 sold for technical purposes in which acidity, odour, colour, etc., do 

 not matter ; they will fetch only a low price but they cost com- 

 paratively little to produce. It is to the improvement of the 

 methods of original preparation that attention must be paid: the 

 Tanur oils from the Government yard show that careful attention 

 to processes means oil that requires little subsequent manipulation 

 and consequently little cost or loss, while they will fetch a superior 

 price; moreover, since West Coast oils are usually required at 

 great distances (e.g., Cawnpore, Calcutta, Dum Dum, etc.) if they 

 are to compete with whale and other imported oils, and since the 

 freight is the same on a ton of good or a ton of bad oil, it pays 

 best to produce and transport good oils. 



134. Dcodorizatio)i. — As already explained, most of the bad 

 odour from which fish oils suffer is due to bad original preparation ; 

 the use of tainted or stale fish, want of immediate and thorough 

 separation of organic impurities and water which cause hydrolysis 

 and the liberation of malodorous acids, scorching by fire, and soon. 

 The best oils, properly prepared, have only a fishy odour, not 

 strong, and comparable with that of good cod liver oil ; this cannot 

 be entirely got rid of, but may be minimised by treatment and 

 by subsequent precautions in storage (paragraph I2l) to prevent 

 subsequent acidity ; such deodorization, if combined with other 

 refinements, fits our fish oils for edible and medicinal purposes for 

 which they have already been used- 



In studying neutralization by sodium carbonate preceded by 

 steaming, it was found that practical deodorization was also 

 effected ; any putrid or accessory smell was always removed, 

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