30 CALORIMETRY 



of CO 2 eliminated to the volume of O absorbed will be 1, as may 

 be deduced from the equation : 



C(H 2 0)+0 2 =C0 2 +H 2 



1 vol = l vol R. Q 



Fats are compounds of the trihydric alcohol, glycerol, with organic 

 acids of the aliphatic (fatty) homologous series. The simplest 

 fatty acid is formic, H-COOH. The higher acids are built up 

 by successive additions of CH 2 . 



TABLE III. 

 SATURATED SERIES. C M H 2 , t O 2 . 



E.g. H-COOH -formic acid CH 2 O 2 



CH 2 -HCOOH acetic acid C 2 H 4 O 2 



CH 2 -CH,-HCOOH propionic acid C 3 H 6 O 2 



CH 2 -CH 2 -CH 2 -HCOOH butyric acid C 4 H 8 O 2 



* 



(CH 2 ) 15 -HCOOH palmitic acid C 16 H 32 O 2 

 (CH 2 ) 16 -HCOOH margaric acid C 17 H 34 O 2 

 (CH 2 ) 17 -HCOOH stearic acid C 18 H 3(J O 2 



UNSATURATED SERIES. C Ho 9 Oo 



n 6?i GI & 



oleic acid C 18 H 34 O 2 



A glance at this list will make it clear that the amount of 

 oxygen does not increase although the C and H are increased. 

 This paucity of oxygen content is more marked in the fats than 

 in the fatty acids. 



Palmitic Acid Glycerol Palmitin 



C 15 H 31 COOH HO 



C ]5 H 31 CO OH H O^C 3 H 5 =C 51 H QS G +3H 2 O 



C ]5 H 31 COOH HO 



C 51 H 98 O 6 +145O=51CO 2 +49H 2 O. 



Vol CO, 51 

 Now ratio^^ =0-70. 



That is, ratio for carbohydrates is 1. 



,, fats ,, 0-7 (circa) 



(Zuntz gives 0-707 as an average figure for fats.) 



(VII) Values for a non-protein ratio lying between 0-7 and 1 

 denote the utilisation by the body of a mixture of fats and carbo- 



