6 PURIFICATION PF FISH-OIt. 



effervefcence which then comes on, rupturing the veficlcs, 

 makes the blabber yield a greater quantity of oil than could 

 be extracted before fuch change was produced ; and the 

 veficles of the tela cellulofa, containing the gelatinous matter, 

 being alfo burft from the fame caufe, fuch matter being then, 

 rendered faponaceous by the putrefaction, a part of it mixes 

 intimately with the oil, and constitutes it a compound of the 

 proper oleaginous parts and this, heterogeneous fluid. 

 How the bile The prefence of the bile in fifti-oil is occasioned by its 



mixed. being, in many cafes, extracted from the liver of the fifh $ 



which is not to be fo profitably done by other means as by 

 putrefaction ; and the bile being confequently difcharged, 

 together with the oil from the veflels of the liver containing 

 them, combines with it, both from the original faponaceous 

 property of bile, and from that which it acquires by putre^ 

 faction. 

 Train oil i$ This holds good particularly of the cod-oil, or common 



particularly train, brought from Newfoundland ; which, from its high 

 yellow colour, vifcid confidence, and repugnance to burn- 

 ing well in lamps, manifefts fenfibly the prefence of bile and 

 the gelatinous fluid ; which latter, by the faponaceous power 

 of the bile, is commixed in a greater proportion in this than 

 in any other kind of fifti-oil, 

 Perfeft oils are A tendency to putrefy, or at moft but in an extremely flow 

 ^utrcf 1 ^ ^ 10 manl ^ er ' is not an abfolute property of perfed oils in a fimple 

 or pure ftate ; but it is a relative property dependant upon 

 their accidental contract or commixture with the aqueou* 

 fluid. This is evident from the cafe of oils concreted into a 

 febaceous form | which being perfectly oleaginous and un- 

 combined with any water, except fuch as enters into their 

 unlefs water be component parts will not putrefy unlefs water, or foraething 

 prefent, containing it, is brought in contact with them, But the 



fluid animal, and moft vegetable oils, being compounded 

 pf perfect oils with other mixed fubflances, either fub- 

 But moft oils oleaginous or gelatinous, have always a putrefcence per fe, 

 will putrefy or tendency to putrefy, without further admixture of aqueous 

 moifture. This commixture of heterogeneous matter in fifh- 

 pij, particularly of the gelatinous fluid and bile, gives rife to 

 even after edul- a further principle of purification thanjlmple edulcoration, or 

 coratiom fa e removing the fetor; for the prefence of fuch humours in the 



oil renders it fubjedi to a fecond putrefcence per fe, fiippofing 



the 



