PURIFICATION OF FISH-OIL. 5 



The Principles oil which the Purification of Fijh-oil may be per* 

 formed, and of the Ufes to which it is applicable. By Robert 

 Dossif. *. 



1 HAT the fetid fraell of fiuVoil is chiefly owing to putre-Fator of fifh- 

 faclion, it is unneceflary tp fhow ; but though this be the !„ t ££a™ n and 

 principal eaufe, there is another likewife, which is, uftion empyreurna. 

 pr burning the oil, occasioned by the ftrong heat employed 

 for the extracting it from the blubber of the larger fifh, and 

 which produces a ftrong empyreumatic fcent that is not 

 jalways to be equally removed by the fame means as the putrid 

 fmell, but remains fometimes very prevalent after that is taken 

 away. 



In order to the perfect edulcoration of oils, there are con- The fa™ 

 fequently two kinds of fetor or ftink.to be removed, viz. [^jf j^ * 

 the putrid, and the empyreumatic.; and the fame means do 

 not always equally avail againft both. 



The putrid fmell of fifh-oil is of two kinds ; the rancid, The oil itfelf 



■which is peculiar to oils j and the common putrid fmell, which ™ n y ci ^ c °™ e it 



is the general efTe£t of the putrefaction of animal fluids, or of may putrefy as 



the vafcular folids, when commixed with aqueous fluids. t0 , us mixture of 



. r n .. ,, other matters. 



Fifh-oil has not only rancidity, or the firlt kind of putrid Fifh-oil has both 



fmells peculiar to oils, but alfo the fecond or general kinds ; thefe putrid 



,..'„, n . • - t • i , i ,- fmells. It w 



fts the oil, for the molt part, is commixed with the gelatinous tains g e i at - m e 

 humour common to all animals, and fome kinds with a pro- and rile. 

 portion of the bile likewife ; and thofe humours putrefying 

 combine their putrid fcent with the rancidity of the oil, and, 

 jn Cafes where great heat has been ufed 4 with that and the 

 empyreurna alfo. 



The reafon of the prefence of the gelatinous fluid in fifli- The gelatine Is 

 oil is this : that the blubber, which con fifts partly of adipofe j. °J^ c ve J£™* 

 veficles, and partly of the membrana cellulofa, which cpn-&c. 

 tains the gelatinous fluid, is, for tlie moft part, kept a cpn- 

 fiderable time before the oil is feparated from it, either from 

 the want of convenient opportunities to extract the oil, or in 

 order to the obtaining a larger proportion ; as the putrid 



* Communicated to the Society for the encouragement of Arts . 

 long ago, but now publifhed by them in the original form. 



efTervefcenc^ 



con,- 



