THE RELATIONS OF METABOLISM TO FOOD-SUPPLY. 177 
respiration experiments made in his laboratory by Lehmann & 
E. Voit with geese and by Rubner with a dog which demonstrated 
a production of fat from carbohydrates. Rubner’s experiment was 
shortly afterward published in full.* It was a respiration experi- 
ment covering four days immediately following a fortnight’s heavy 
feeding with meat. On the first two days of the experiment the 
animal fasted and on the second two received only starch and cane- 
sugar. The results for the last two days were: 
Proteid metabolism................ 15.94 grams. 
Equivalent fat, according to Rubner.. 7.65 “ 
Fat of food. .... 0.0.0... 69.400 
Maximum from fat and proteids...... 17.05“ 
Fat actually produced.............. 117.25 “ 
Even after making all possible deductions for the fact that some 
carbon may have been retained in the body in the form of glycogen 
instead of fat, and also for a possible residue of undigested starch in 
the alimentary canal at the close of the experiments, Rubner still 
computes that at least 40.7 grams of fat must have had its origin 
in carbohydrates. 
Lehmann & E. Voit’s experiments have only recently ap- 
peared.t In their introduction they report also the results of ex- 
periments on fattening geese made by C. Voit several years previous 
to 1883, which likewise show a production of fat from carbohydrates. 
G. Kithn and his associates,{ at the Méckern Experiment Station, 
have demonstrated, by means of respiration experiments in which 
starch was added to rations but slightly exceeding the maintenance 
requirement, a formation of fat from carbohydrates by ruminants 
(oxen). In view of the possibility (see p. 27) that part of the car- 
bon of the urine may be derived from the non-nitrogenous matter 
of the food, and in order to be on the safe side, the authors assume 
as possible that all the carbon of the proteids metabolized may 
have been stored up in the body in the form of fat. On this extreme 
and improbable assumption their results were as shown on the 
following page: 
* Zeit. f. Biol., 22, 272. 
t Ibid., 42, 619. 
¢ Reported by Kellner; Landw. Vers. Stat., 44, 257. 
