IMPROVED METHODS FOR FAT ANALYSIS. 137 



saponifiable matter in the dry state, therefore, promises more trustworthy 

 results, although it is a more lengthy process and not entirely free from 

 criticism. 



The unsaponifiable matter of oils and fats consists principally of the 

 solid alcohols of the cyclic or aromatic series, the so-called sterols (sitos- 

 terol, stigmasterol, brassicasterol and cholesterol). In some products 

 occur alcohols of the ethane series (ceryl and meUssyl) and hydrocarbons, 

 also small amounts of coloring matter, resinous substan,ces, ethereal oils, 

 nitrogenous bodies (lecithin, mucilaginous matter), etc. 



Sitosterol is the characteristic concomitant of vegetable oils and fats, 

 and cholesterol of animal. The former alcohol is sometimes accompanied 

 by stigmasterol or brassicasterol. Stigmasterol has been found in soy 

 bean oil, calabar bean oil and rape oil. 



Ceryl and melissyl alcohols are the only members of the ethane series 

 that appear to have been identified. 



Hydrocarbons have been reported in buckthorn oil, kosam seed oil, 

 parsley seed oil, cantharides oil, chrysalis oil, laurel oil and cacao butter. 

 The unsaponifiable matter of laurel oil has a high iodine number. The 

 chromogenic bodies give the color reactions in identification tests of cot- 

 tonseed, sesame, fiver oils, etc. Ethereal oils occur in nutmeg butter. 



Remnants of vegetable or animal tissue are purely adventitious sub- 

 stances, and should always be excluded. 



Among extraneous substances that may appear in the imsaponifiable 

 matter are mineral oils (petrolatum and shale oils), tar oils (neutral coal 

 oils), paraffin, ceresine, rosin oils, etc. They occur in the oils and fats as 

 adulterants. 



The amount of unsaponifiable matter in oils and fats varies from a 

 trace to several per cent. Corn, cottonseed and sesame oils show over 1 

 per cent, in some instances, while rape, peanut and oUve oils appear to 

 average less. Fish, fiver and blubber oils, such as herring, cramp fish, 

 cod liver, shark liver, whale and porpoise oils, sometimes contain 10 or 

 even 20 per cent. Old rancid fats yield larger amounts than fresh fats. 



The unsaponifiable matter of waxes includes alcohols of the ethane 

 serifes (cetyl, ceryl, melissyl, etc.), of the cyclic series (sitosterol, choles- 

 terol and isocholesterol) and of several other series seemingly less promi- 

 nent, and of hydrocarbons. The alcohols in the natural product evidently 

 occur both free and in combination with fatty acids as esters. They are 

 mostly monatonuc, the more common belonging to the ethane series. 



Sitosterol is found in vegetable flax wax, and cholesterol and isocholes- 

 terol in wool wax and probably in beeswax. 



Hydrocarbons constitute an appreciable amount in waxes, particularly 

 in the case of the solid waxes. 

 Adulterants similar to those of oils and fats may be expected. 

 The unsaponifiable matter in Uquid waxes varies from 31 to 43 per 

 cent., and in sofid waxes from 43 to 55 per cent. 



