ECONOMIC USE OF FATS 3 



the leaves of evergreen plants during the winter months. The 

 fat-like substances, according to Meyer,* who studied Vinca, 

 Taxus and Ilex, do not show a seasonal variation in amount, 

 but continually increase with the age of the leaf. These 

 phenomena are similar to those which will be mentioned in 

 connexion with the conversion of starch into sugar under the 

 influence of low temperature (p. 132). 



The majority of vegetable fats are fluid at ordinary tem- 

 peratures ; a few, however, are solid, for instance, cacao butter 

 and the fat in the seeds of Myristica. 



INDUSTRIAL USES OF VEGETABLE FATS ^ND OILS. 



Economically, fats are of considerable value, being used for 

 food, illumination, lubrication, soap manufacture, and for a 

 variety of other purposes. 



The following is a brief consideration of some of the more 

 important industrial uses of the commoner fats and oils of 

 vegetable origin. 



OLIVE OIL is extracted from the fleshy pericarp of the 

 fruit of the olive, Olea europaea, by pressure. The best quality 

 oil, which is expressed without the application of heat, is 

 used for food ; lower grade oils, obtained by extracting the 

 residues from the presses with fat solvents, such as carbon 

 disulphide or light petroleum, are used in the manufacture 

 of soap (see p. 5). 



COTTON-SEED OIL is extracted from the seeds of Gossypium 

 herbaceum by pressing them at a temperature of about 90 ; 

 the crude brown oil is purified by treatment with caustic soda 

 which removes the free fatty acids, colouring matter and 

 other impurities. After purification the oil is light yellow in 

 colour. It is used for the manufacture of soap and rubber 

 substitutes. 



COCO-NUT OIL is obtained from the ripe seeds of Cocos 

 nucifera and Cocos butyracea by pressure ; the dried endo- 

 sperms, known as Copra, are imported into Europe and the oil 

 extracted from them is commonly known as Copra oil. Soaps 

 made from coco-nut oil have the property of absorbing large 



* Meyer : " Ber. deut. bot. Gesells.," 1918, 36, 5; see also Tuttle: "Ann, 

 Bot.," 1919, 33, 201. 



