190 EXPERIMENT STATION RECORD. 



furnished the remainder, 76.5 gm. Assuming the formation of glycogen, 

 as E. Yoit had done in his experiments with a goose, there still remained 

 41.8 gm, of carbon which it must be assumed was furnished by the car- 

 bohydrates. Thus a proof of the formation of fat from carbohydrates 

 in Carnivora also was furnished by Munk and Rubner. 



E. MeissP made experiments with pigs, feeding them rations with 

 diflterent nutritive ratios. The i)igs were first fed in 2 experiments a 

 ration of rice, the nutritive ratio being 1:11.8 and 1:13.7, respectivel3^ 

 They were then fed a ration of barley, the nutritive ratio being 1:7. 

 And finally they were fed a mixture of rice, meat meal, and slightly 

 sour whey, the nutritive ratio being 1:2.11, The respiratory products 

 were measured with a Pettenkofer respiration apparatus. It was found 

 that in the first experiment, with the wide nutritive ratio, from 88,2 to 

 88.3 per cent of the fat accumulated must have been formed from starch, 

 and in the second experiment 71 per cent. In the third case (meat meal 

 ration), with a narrow nutritive ratio, 1.0 per cent of the fat must still 

 have been formed from starch. In these experiments 100 gm, of starch 

 yielded 19,0, 23.1, and 11.9 gm. of fat, respectively. The possible theo- 

 retical amount is 41.5 per cent of fat. In the rice ration more than one- 

 half and in the barley ration more than one-fourth of the fat theoretic- 

 ally possible was actually formed from carbohydrates. Up to this time 

 Voit had observed the formation of no more than 12 per cent of fat from 

 protein. 



Briefly recapitulating, Munk's theory^ that fat is formed from the 

 excess of fat or fiitty acids, carbohydrates, and protein in the food con- 

 sumed would have been regarded as final but for the new work pub- 

 lished from 1891 to 1894, When Pfliiger^ formulated his new theory 

 that protein, when present, was the sole source of muscular energy, he 

 raised the question whether or not it was necessary that a cleavage of 

 protein into fat should take place in the animal body before muscular 

 energy could be produced.* He examined in detail all the proofs of the 

 formation of fat from protein offered by Voit. In the first place, Pet- 

 tenkofer and Yoit's computation seemed to rest on a false assumption 

 of the composition of meat. Voit did not take into account the fact 

 that lean meat ordinarily contains 0,91 per cent of fat and 0,5 per cent 

 of glycogen. If on a diet of lean meat all the nitrogen is recovered in 

 the excretory products, but a part of the carbon consumed is retained, 

 it is very possible that protein was split up and used for carrying on the 

 life processes of the organism, while the glycogen and fat contained in 

 the meat consumed was stored up in the body. Further, Voit assumed 

 ahigher carbon content and a lower nitrogen content for lean meat than 

 was found by Playfair, Boeckmann, Rubner, and Pfluger. According 



iZtscbr. Biol., 22 (1886), p. 63. 



-Muuk und Uffelmaun, Die Eruahrung des gesundeu uud krauken Mensclien, 2d 

 ed., 1891, p. 55. 



spfliiger's Arch. Physiol., 50 (1891), p. 98. 

 ^Pfluger's Arch. Physiol., 51 (1892), p. 229, 



