FAT METABOLISM 



733 



shown by, first of all, starving an animal so as to clear the depots of fat 

 as much as possible; then feeding- it on some " ear-marked " fat (unusual 

 melting-point or a brominized fat) ; and after another day or so of 

 starvation, so as to clear the liver itself of fat, poisoning the animal 

 with phosphorus or phlorhizin. The liver will be found shortly after- 

 wards to be invaded with fat which has all the ear-marks of that on 

 which the animal had been fed. 



Evidence of the same character has been furnished in a series of clin- 

 ical cases by observations on the amount of fat and the iodine value of 

 the fatty acid of the liver. This is shown in the accompanying table. 



FATTY ACIDS OF LIVER 



This table clearly shows that the more fat there is in the liver, the 

 nearer this fat approaches in character that stored in the depots. 



That some of the fat in the liver may come directly from the fat re- 

 cently absorbed from the intestine is also very readily demonstrable. 

 Thus, when cocoanut oil was placed in the intestine of anesthetized an- 

 imals, along with bile salts and glycerine, it was found by Raper 52 that 

 30 per cent of the absorbed oil appeared in the liver. 



The characteristic feature of cocoanut oil is that its fatty acids are volatile in steam 

 and are saturated. Some of the fatty acids of the liver are volatile in steam, but they 

 are unsaturated. By distillation in steam of the fatty acids obtained by saponification 

 of the liver, it is possible to determine how much of the cocoanut oil has passed to the 

 liver. 



Similar results have been obtained when unsaturated fatty acids, such 

 as those contained in cod-liver oil, are fed. In all these cases the rela- 

 tionship of the liver fat to that of the food is even more evident than 

 that between food fat and depot fat, because in the liver the newly absorbed 



