134 PHYSIOLOGICAL CHEMISTRY. 



aid in its absorption. That bile is of assistance in the absorption 

 of fat is indicated by the increase of fat in the feces when for any 

 reason bile does not pass into the intestines. 



The fat distributed throughout the animal body is formed partly 

 from the ingested fat and partly from carbohydrates and the 



FIG. 36. 



MUTTON FAT. (Long.} 



"carbon moiety" of protein material. The formation of adipocerc 

 and the occurrence of fatty degeneration are sometimes given as 

 proofs of the formation of fat from protein. This is questioned 

 by many investigators. Rather more satisfactory and direct proof 

 of the formation of fat from protein material has been obtained 

 by Hofmann in experimentation with fly-maggots. The normal 

 content of fat in a number of maggots was determined and later 

 the fat content of others which had developed in blood (84 per 

 cent of the solid matter of blood plasma is protein material) was 

 determined. The fat content was found to have increased 700 to 

 noo per cent as a result of the diet of blood proteins. The cele- 

 brated experiments of Pettenkofer and Voit, however, have fur- 

 nished what is, perhaps, the most substantial positive evidence of 

 the formation of fat from protein. These investigators fed dogs 

 large amounts of lean meat, daily, and through subsequent urinary 

 and fecal examinations were enabled to account for only part of 

 the ingested carbon, although obtaining a satisfactory nitrogen 

 balance. The discrepancy in the carbon balance was explained 

 upon the theory that the protein of the ingested meat had been 

 split into a nitrogenous and a non-nitrogenous portion in the organ- 

 ism, and that the non-nitrogenous portion, the so-called ''carbon 



