188 EXPERIMENT STATION RECORD. 



been formed from protein, and 15 to 33 per cent mnst have been formed 

 from carbohydrates, Soxhlet himself made 3 experiments with Yorli:- 

 shire j^igs which he fed with rice, a food poor in protein and fat but 

 rich in starch and also free from amids. One pig gained 10.082 kg., 

 and another L*LM8 kg. In one case protein could yield 1.779 kg. of fat, 

 and in the other case 3.685 kg. It will be seen that the pigs produced 

 5 or 6 times more fat than could have been formed from the protein and 

 fat in the food. 



B. Schulze' made an experiment with 8 geese. They were divided 

 into groups of 2 each and were fed with different mixtures of rye bran 

 and potato starch. Schulze assumed the formation of fat from aspara- 

 gin, but it has not been proved, and he calculated the hypothetical 

 quantity of fat by Henneberg's method. In one case 13 per cent and 

 in another 17.0 per cent of the total quantity of fat formed must have 

 been derived from carbohydrates. 



N. Tschirwinsky ^ fed pigs with barley alone and with the addition of 

 starch and sugar. In one case there was a gain of S,570 gm. of fat, and 

 only 3,707 gm. could have been formed from the fat and protein in the 

 food — that is, 4,869 gm. must have been formed from carbohydrates. 

 In another case there was a gain of 5,429 gm. of fat, only 1,525 gm. of 

 which could have been derived from the protein and fat in the food. 



S. Chaniewski ' made experiments with geese, and found a gain of 

 209 gm., 640.2 gm., and 445.24 gm. in the different cases, of which 75.3 

 gm., 136.52 gm., and 60.08 gm., res])ectively, could have been formed 

 from the fat and protein assimilated from the food — that is, 71.7, 78.6, 

 and 86.7 per cent must have been formed from carbohydrates. 



As late as 1881 Voit* still held to his old opinion, but through the 

 accumulated evidence was compelled to acknowledge the possibility of 

 a formation of fat from carbohydrates. In a lecture "On the formation 

 of fat in the animal body," delivered in 1886, Voit said that he had 

 never denied the possibility of the formation of tat from carbohydrates; 

 he had simply said it was not proved, and if this proof was now fur- 

 nished i4»did not follow that he had erred in his judgment. The new 

 experiments of Soxhlet, Tschirwinsky, iSchulze, and Chauiewski all 

 contained errors, since all assumed a hypothetical value for the com- 

 position of the animal body at the' beginning of the experiment which 

 can not always be determined with accuracy by analyzing the flesh of 

 another similar animal. Pettenkofer's resi)iration apparatus, in which 

 all the excretory products were measured, offered an exi)erimental 

 method free from error. 



Erwin Yoit and C. Lehmann had made exijeriments with geese and 

 determined the respiratory i)roducts. On the first day of feeding the 



iLandw. .Jahrb., 11 (1882), p. 57. 



2Lan(lw. Vers. Stat., 29 (1883), p. 317. 



sztschr. Biol., 20 (1884), p. 179. 



* Hermann's Handbuch der Physiologie. vol. 6. 



