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 _ r COOH is de- 

 rived from an alcohol with the formula C n H 2n+1 .HO. Thus ordi- 

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

 of hydrogen in the process of oxidation gives ethyl aldehyde, 

 CH 3 CHO ; 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 3 (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 n _,H 2n _ 3 .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. iyth Ann. Rep. 175-217. 1893. 



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

 Sta. i8th Ann. Rep. 147-191. 1894. 



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

 Chem. Soc. 18 : 1-15. 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, O. Chemie der Eiweisskorper. 1900. 



