108 MANUAL OF . CxlTXLE-FEEDIIS^G. 



Ilolieiilieim experiments on swine, tliat the absolnte quan- 

 tity of these products in the excrement is no greater with 

 a rich than witli a poor fodder. 



Digestibility of Fat. — The determinations of the di- 

 gestibility of f<Mb hitherto made in digestion experiments 

 are much less exact than those of the digestibility of albn- 

 mhioids. Most of the biliary products are soluble in ether, 

 and as the ordinary fodder of domestic animals contains 

 but a small quantity of fat, by the addition of these pro- 

 ducts to the actual fat contained in the excrement the 

 apparent digestibility of the f^t must evidently be very 

 considerably decreased, and the more so the less of it is 

 contained in the fodder. 



In some experiments by E. v. Wolff, at ITohenheim,* on 

 swine, the animals were fed exclusively with potatoes — a 

 fodder containing but little fat — and the absolute quantity 

 of cnide fat (or, more correctly, of matter soluble in ether) 

 in the excrement was considerably greater than that con- 

 tained in the fodder, amounting to 9.48 gnns., and 10.95 

 grms. per day and head, against 4.27 grms. and 4.91 grins, 

 in the fodder- 

 But, notwithstanding this source of error, digestion ex~ 

 periments yield results for fat which, although by no 

 means absolutely correct, are yet, to a certain extent, com- 

 parable, and have a certain worth in estimating the val^ie 

 of a fodder, though it must always be borne in mind that 

 they are too low, and the more so the poorer the fodder is 

 in fat. "We have already learned that the results obtained 

 in fodder analysis are only approximate. They do not 

 represent pure substances, but serve, when all analyses are 

 carried out in the same way, to compare different fodders 



Landw. Jakrbucher, VIII., I. Supplement, p S02. 



