298 THE ROTHAMSTED EXPERIMENTS. 



Experi- In experiments made by Kern and Wattenberg, at Gotting- 



rnents m en i w j t ^ sheep of various ages, in ten cases the fat stored up 

 with sheep, fell short by 24 to 64 per cent of that which could have been 

 derived from the fatty matter and nitrogenous substance con- 

 sumed. In one experiment, however, one animal was killed 

 and the initial composition determined, and the other was fed 

 for ten weeks, and the composition and digestibility of the 

 food were determined. The results showed that 29.4 per cent 

 of the fat stored up must have been derived from other sources 

 than the fat and the albumin of the food ; and, even making 

 all allowance for possible error, it was concluded that fat must 

 have been derived from the carbohydrates consumed. 



In other experiments at Gottingen, by T. Pfeiffer and 

 Lehmann, 2 a similar result was obtained with a sheep fed with 

 a considerable quantity of sugar. 

 Wolff's ex- In an experiment made by Wolff at Hohenheim, 3 a young 

 wit^ias P^§ was ^ ^ or 1^8 days with barley and maize-meal, with the 

 addition of pure starch. The constituents digested were deter- 

 mined. Eeferring to the results, Wolff says that, having re- 

 gard simply to the amounts of constituents consumed, and of 

 increase produced, it is scarcely possible to suppose that the 

 quantity of fat which must have been stored up could have 

 been formed without the co-operation of the carbohydrates. 

 He points out that fat equal to only 29 per cent of the increase 

 in live-weight could have been produced from the fat and the 

 albumin of the food; and in this calculation he takes the 

 whole of the albumin as available, without reckoning any to 

 have been stored up. He adds that, according to the percent- 

 age of fat in increase in the Eothamsted experiment No. 1, 

 Rotham- there must have been 60 per cent or more. According to our 

 s *t d ™ w °f own calculation of Wolff's results, it seems probable that 

 periment. about 60 per cent of the total fat in the increase must have 

 been derived from carbohydrates. It is particularly to be 

 observed that, in the case of this experiment, Wolff concluded 

 that the formation of fat from the carbohydrates might be 

 considered established, not only without any respiration 

 apparatus, but even without any direct determination of fat 

 in the animal. 

 Various ex- Wolff quotes the results of experiments with pigs at 

 gJJSSjJ Moscow, by Tschirwinsky, in 1880-81 and in 1881-82. 4 It 

 Rotham- was estimated that in the one case 61.6 per cent, and in 

 sted results. fo Q other 76.9 per cent of the fat of the increase must have 

 had its source in the carbohydrates of the food. 



1 Joum. fur Landw. Jahrg. 26, p. 549. 



2 Joum. fur Landw. 1885, Band 33, p. 337 ; also 1886, Band 34, p. 83. 



3 Die rationelle Fiitterung der landwirthschaftlichen Nutzthiere, 5 te Aufl., 

 1888, p. 48. 4 Versuchsstationen, 1883, Band 29, p. 317. 



