Formation of Fatty Acids 



263 



This gross comparison between plasma and milk fatty acids 

 indicates that synthesis of fatty acids in the udder from small 

 molecules (e.g. acetate or some other C2 unit) is of primary 

 importance in the origin of milk fat. It has been possible 



40 r 



10 



20 30 



Time after injection (hr.) 



Fig. 2. Specific activity: time curves of 4 crude fatty acid 

 fractions obtained from milk glycerides of a goat after tlie injec- 

 tion of 5 mc. CHa^COONa. 



Steam volatile water-soluble fatty acids. 



^ Steam volatile water-insoluble fatty acids. 



• Non-volatile solid acids. 



A Non-volatile liquid acids. 



(Popjak, Folley and French, 1950, 1951.) 



to calculate the amount of acetate used for milk fat synthesis 

 during the first six hours of the experiment. Eighty per cent 

 of the injected acetate appeared as respiratory COg, and 10 

 per cent of the total dose, or 50 per cent of the acetate retained 

 in the body, was converted into milk fatty acids. If we 



