FATS 179 



moiety" of protein material. The formation of adipocere 1 and the 

 occurrence of fatty degeneration are sometimes given as proofs of the 

 formation of fat from protein. This is questioned by many investiga- 

 tors. 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 in- 

 creased 700 to 1 1 oo per cent as a result of the diet of blood proteins. 



FIG. 51. MUTTON FAT. (Long.} 



The celebrated experiments of Pettenkofer and Voit, however, have 

 furnished 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 examination of urine, feces and 

 expired air 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-nitroge- 

 nous portion in the organism, and that the non-nitrogenous portion, the 

 so-called " carbon moiety" of the protein, had been subsequently trans- 

 formed into fat and deposited as such in the tissues of the organism. 

 Later evidence in favor of the formation of fat from protein has 

 been furnished by the experiments of Weinland. This . investigator 

 worked with the larvae of Calliphora, 2 these larvae being rubbed up 

 in a mortar 1 with Witte's peptone and water to form a homogeneous 



1 A very complete analysis of adipocere was reported by Ruttan and Marshall before 

 the Society of Biological Chemists, Boston, Dec. 27, 1915. 



2 The ordinary "blow-fly." 



