FATS AND OILS 



143 



Fats and Fatty Oils. — Con. 



Palmitic acid 



Cl6H3202,(Cl5H31-COOH) 



Stearic acid 



C18H36O2, (C17H35 — COOH) 

 Oleic acid 



C1SH34O2, (C17H33 — COOH) 

 Ricinoleic acid 



C18H34O3 

 Linoleic acid 



Cl8H3202 



Crotonic acids 

 C4H6O2 



Aromatic Oils and Camphors. 



alcohol glycerine and various 

 fatty acids. They are mostly 

 liquid (i.e. oils) in plants but 

 in some tropical plants are 

 soUd at ordinary temperatures. 

 Usually they are mixtures of 

 several fats, the three most 

 common ones being the same 

 as the commonest animal fats, 

 viz.: the first three named 

 below. Upon the propor- 

 tions of the three depends 

 whether the fat will be solid or 

 liquid. The acids concerned 

 are: 



Forming with glycerine a 

 solid fat, palmitin. 

 Forming with glycerine a 

 solid fat, stearin. 

 Forming with glycerine a 

 liquid oil, olein. 

 Forming with glycerine a 

 liquid oil (castor oil). 

 Forming with glycerine a 

 liquid oil (in hnseed oil). 

 Of which several isomeres are 

 known, are found in their glyc- 

 erine esters in croton oil. 

 These are oily hquids or crys- 

 talUne solids, mostly "ben- 

 zene derivatives," occurring 

 in fruits, leaves and stems of 

 many plants. The oily spots 

 made by the oils disappear on 

 evaporation. Very many are 

 known but in many cases the 

 composition is not satisfac- 

 torily worked out. Chemically 

 they are very variable. Those 

 mentioned below are all very 

 closely related to each other. 



