224 MADRAS FISHERIES BULLETIN VOL. XIII, 



of impurities, which flows with the oil into the receiving pits, must 

 be rapidly separated from the oil and the oil well washed with 

 boiling water which must also be rapidly separated ; the oil must 

 then be " dried," that is, deprived of any residual water in minute 

 suspension in the oil ; and, finally, the washed and dried oil must 

 be stored in proper receptacles, free as far as possible from the 

 influence of air, light, and moisture. 



124. Use of salt. — This addition to the material is important. 

 It should be a rule to mix salt in sufficient quantities with all 

 fish which cannot be worked off" in, at most, 12 hours' continuous 

 work ; such addition would entirely prevent taint, and would con- 

 sequently improve the quality of the oil and minimise offensiveness, 

 In paragraph 5 on page 54 and paragraph 8 on pages 69 and 70 of 

 Bulletin X, it is shown that ungutted sardine fresh from the sea can 

 be preserved for a considerable period by being simply " roused " 

 (thoroughly mixed) with salt, the proportion of salt not exceeding 

 one-seventh of the weight of fish ; for very short periods a smaller 

 proportion suffices. Hence all that is necessary when sardines are 

 received in excessive quantity is to rouse with, say, 10 per cent of 

 salt, all sardines in excess of the quantity which can at once be 

 worked off. This causes some extra expense but produces the 

 following advantages : — 



(1) prevention of taint and consequently, 



(2) superiority of oil both in colour, odour, and value ; 



(3) obviation of public nuisance ; 



(4) ability to work at leisure so that work is better and 

 necessary rules can be observed; 



(5) greater readiness of the oil and water to separate in the 

 separating pits owing to the increased specific gravity of the 

 water ; 



(6) diminished tendency of the contents of the effluent water 

 to putrefy, and consequent avoidance of nuisance and ability to 

 handle it ; 



(7) benefit when irrigating coconut trees which approve of 

 salt ; if too saline it can readily be diluted. 



REFINEMENT. 



125. The refinement of menhaden oil is mentioned in para- 

 graphs 39 and 40 supra ; generally speaking fish oil is not refined 



