No. 3 (1921) MANUFACTURE OF FISH OIL AND GUANO 225 



to any great extent, and, as mentioned in the preceding paragraph, 

 on the Madras coast the product is almost entirely sold as 

 oil-cum-stearine. But it appears probable that Madras sardine 

 oils (and possibly liver oils) may, if refined, be useful in ways which 

 at present are not at all or very slightly possible or even contem- 

 plated ; for instance in first qualities as edible oils in canning, or 

 as medicinal oil, or for hydrogenation into edible fats ; in second 

 qualities for leather, paints, etc., for which the crude oils are un- 

 suitable ; or, again, for hydrogenation as soap fats. Hence a brief 

 description will be given of refining methods, as taken partly from 

 text books (see list of authorities in the Appendix) to which refer- 

 ence must be made for details, partly from local experiments. 



But it should be remarked that West Coast sardine oils pre- 

 pared from fresh or untainted fish, boiled by steam, rapidly and 

 thoroughly separated from the effiuent water, t/ioroxglily washed at 

 once to remove impurities, the residual water (in suspension) 

 removed as soon as possible, and the oil then stored in air-tight 

 receptacles such as sound casks, etc., requires very little purifica- 

 tion ; it was fine yellow A. I. oil. prepared as above without subse- 

 quent refinement or any treatment save that mentioned, which was 

 characterized by a firm in Great Britain as "unique " ; similar oil 

 has long been used in the sardine cannery not merely for frying 

 but also, in due proportion with vegetable oils, in packing the tins 

 of fish ; it has also been accepted as medicinal oil, and consumed 

 without demur, being almost inodorous, tasteless, and free from 

 acidity. But even this oil may be further improved by refining 

 processes for the above purposes, while the common oil can be 

 greatly elevated in class and consequently in the scope of its uses 

 and therefore in demand and in ^price, by refining methods. But 

 refinement is only needed for certain classes of work, and, in any 

 case, should be suited to the oils in hand and to the intended uses 

 of such oils. The methods will be briefly described under the 

 sub-heads of purification, clarification, filtration, dehydration, 

 neutralization, deodorization, bleaching, and removal of stearine. 

 For further details various text books must be studied. 



126. Purification. — Crude fish oil straight from the separating 

 tanks is usually contaminated by minute fragments of fish, by 

 albuminous fluid matter, and by a certain amount of water contain- 

 ing gluey and other matters. The organic matters rapidly putrify 

 and so give to the oil part of its malodorous character, while 



