86 EXPERIMENT STATION. [Jan. 



butter fat might be attributed in part to the bean protein and 

 in part to the bean oil. A careful study of the analytical data 

 fails to reveal any marked differences that could be attributed 

 to the change in the ration. In the butter fat from Herd II. 

 the higher iodine number might indicate a small increase in 

 the amount of unsaturated acids beyond that resulting from the 

 advance in the period of lactation. If such were the case the 

 increase in all probability would be attributed to the influence 

 of the oil rather than to the bean protein. 



In the third period, when the bean meal was replaced by 

 the normal ration (Herd II.) and an average per day and head 

 of .6 of a pound of soy bean oil was added, striking differences 

 are noted. In case of Herd I. (normal ration) the Kottsdorfer 

 number dropped from an average of 234.58 to 231.97, — some 

 31/0 points, — while with Herd II. it fell from 231.59 to 221.65, 

 — a difference of 10 points. The former decline was due 

 largely to the advance in the milking period, and perhaps to a 

 slight decomposition in the fat, while the latter decline must 

 have resulted, to a considerable extent, from the feeding of the 

 bean oil. The Reichert-Meissl number in the fat of Herd I. 

 fell slightly from that in the second period (29.23 to 29.02) ; in 

 the fat from Herd II. it dropped from 27.05 to 23.27, showing 

 a marked decrease in the amount of soluble fats. The iodine 

 value of the fat produced by Herd I. was similar to that in 

 the second period, while with Herd II. it increased from 31.90 

 to 40.25, giving additional evidence of the increase of oleic 

 and possibly of linolic acids. In terms of oleic acid, by calcula- 

 tion,^ this increase amounts to 9.26 points, it being 35.42 in 

 the second period and 44.68 in the third period. 



The determination of the important constants, therefore, 

 makes clear that the addition of the bean meal, with a high 

 percentage of bean protein, had little if any effect upon the 

 chemical composition of the butter fats. The feeding of the 

 bean oil, on the other hand, depressed the volatile fats and no- 

 ticeably increased the percentage of unsaturated acid. Whether 

 the bean oil entered directly into the butter fat molecule without 

 change resulting from its passage through the digestive and 



1 Oleic acid =: ^p<^'°^ Dumber (,,.,^,,.^1 (,„ -^ ,.on)bining weight of 127 for iodine). 



