CATABOLISM OF FATTY ACIDS 393 



carbon atoms, we would obtain butyric acid and from this 

 /?-oxybutyric acid, diacetic acid and acetone : 



ACETONE 

 CH 3 



CO + C0 2 . 



CH 3 



There follows now the very interesting fact that if various 

 acids are added to the blood perfused through the living 

 excised liver of a dog, the acids with even number of carbon 

 atoms (butyric acid, C 4 ; caproic acid, C 6 ; caprylic acid, C 8 ; 

 capric acid, C 10 ) give rise to a notable acetone formation; 

 while in case of the acids with uneven number of carbon 

 atoms the amounts! of acetone formed are no greater than 

 when the liver is perfused with normal blood. Embden 32 

 properly says that the supposition that fatty acid catabolism 

 takes place in the manner described has been made much 

 more probable by these experiments. It should be definitely 

 understood that, provided the oxidation of a carbon chain in 

 the body takes place at the /?-carbon atom (as we have every 

 reason for assuming, following Knoop) we can never obtain 

 from a normal fatty acid with an uneven number of carbon 

 atoms ^-oxybutyric acid and acetone ; for example : 



CH, CH, 



CH 2 CH 2 CH, CH..OH 



CH 2 * CH.OH > CH 2 > CH, 



CH, in, COOH ioon. 



COOH COOH 



Reference will again be made to these points, which argue 

 a direct relation between the acetone bodies and fat disinte- 

 gration in the economy, when the former are discussed. Con- 

 sideration of the occurrence of the lower fatty acids in milk 



13 G. Embden and A. Marx, 1. c. 



