THE FATS 167 



are desired, the student is referred to the works of Osborne, 

 Campbell, Wiley and others. 1 



235. The Fats. A fat is a compound of glycerine with fatty 

 acid. Fats are composed simply of carbon, hydrogen and oxy- 

 gen. Glycerine is a trihydric alcohol and unites with three mole- 

 cules of a fatty acid to form an oil or a fat. For this reason the 

 neutral fats and oils are usually spoken of as triglycerides. The 

 monatomic alcohols by oxidation give rise to a series of fatty 

 acids. The acid with the general formula C n _ 1 H 2n _ 1 .COOH is de- 

 rived from an alcohol with the formula C H, ^.HO. Thus ordi- 

 naiy ethyl alcohol, CH 3 CH 2 OH, by the removal of two atoms 

 of hydrogen in the process of oxidation gives ethyl aldehyde, 

 CH3CHO ; further oxidation by the addition of an atom of oxy- 

 gen forms acetic acid, CH 3 .COOH. The radicle of acetic acid is 

 called acetyl and when this radicle unites with glycerine, C 3 H 5 - 

 (HO) 3 , to replace the three atoms of hydroxyl, the result is tri- 

 acetin, C 3 H 5 (O.CH 3 CO) 3 , which is a type of a neutral fat. Simi- 

 larly tristearin , tripalmitin and triolein are obtained from stearic, 

 palmitic and oleic acids respectively. Oleic acid, however, be- 

 longs to a somewhat different series, the general formula for which 

 is C^H^.COOH. 



The neutral fats have the following general properties : 



(a) When pure they are odorless, tasteless and colorless. 



(b) They are lighter than water. 



1 Wiley, H. W. Principles and Practice of Agricultural Analysis. 3 : 1897. 



Wiley, H. W. Composition of Maize. U. S. Dept. of Agric, Div. of Chem. 

 Bull. No. 50. 1898. 



Osborne, Thos. B., and Voorhees, Clark L. Proteids of the wheat kernel, kidney 

 bean and cotton seed. Conn. Ag. Exp. Sta. 17th Ann. Rep. 175-217. 1893. 



Osborne, Thos. B. Studies of the proteids of rye and barley. Conn. Ag. Exp. 

 Sta. 1 8th Ann. Rep. 147-191. 1894. 



Osborne, Thos. B. and Campbell, George F. Conglutin and Vitellin. Jour. Am. 

 Chem. Soc. 18 : 1-rS. 1896. 



Osborne, Thos. B. Some definite compounds of protein bodies. Jour. Am. Chem. 

 Soc. 21 : 486-493. 1899. 



Osborne, Thos. B., and Campbell, George F. The nucleic acid of the embryo of 

 wheat and its protein compounds. Jour. Am. Chem. Soc. 22 : 379. 1900. 



Cohnheim, 0. Chemie der Eiweisskorper. 1900. 



