1901.] PUBLIC DOCUMENT — No. 33. 17 



relative amount of fat in the milk. The full data proving 

 tliis statement has not been published. The conclusion of 

 several American experimenters who had previously fed dif- 

 ferent fats to dairy animals was that no positive increase was 

 to be observed. Soxhlet sug<>cstcd that the reason the effect 

 of " food fat " had not been more pronounced was because 

 the fat or oil fed had not been digested and assimilated by 

 the animals. Following out the suggestion made by our first 

 experiment, and endeavoring to prove or disprove Soxhlet's 

 statements, several experiments were instituted. 



The first two were made with three animals, — the only 

 ones in condition at the time, — in the summer of 1898, and 

 have ])ecn designated Experiments I. and II. It was merely 

 a i)reliminary test. These animals were in rather an advanced 

 stage of lactation, but producing 15 to 20 pounds of milk 

 each per day. The coarse feeds during the several periods 

 consisted of first and second cut hay, or second cut hay and 

 green feed. The grain feed during the ' ' normal oil " })criods 

 was wheat bran, or liran and Chicago gluten meal ; and in 

 the so-called " excess oil" periods flaxseed meal* was added 

 to tlie wheat bran, or was substituted for the Chicaijo gluten 

 meal. In the normal oil periods the amount of oil calculated 

 to be digested was from .4 to .5 pounds, and during the ex- 

 cess oil periods from 1.4 to 1.8 pounds. The normal oil 

 periods lasted seven days, then followed excess oil period 

 of ten days, subsequently normal oil periods of four days. 

 Each period proper was preceded by a preliminary period 

 of seven days. When the excess oil was fed, the fat of the 

 milk increased one-half per cent, in almost every case (that 

 is, from 5 to 5.50, for example), and in some cases even 

 more, and dropped back again when the excess oil Avas re- 

 moved to even below what it was in the first or normal oil 

 period. Part of the increase might be attributed to change 

 of feed. The periods were shoii and the weather warm, and 

 the experiment could be considered of only sufficient impor- 

 tance to warrant still further investigations under more favor- 

 able conditions. 



• This meal contained about 37 per cent, of linseed oil. 



