1909.] PUBLIC DOCUMENT — No. 31. 91 



The Valenta test, as modified by Allen/ was employed in 

 securing the reported results, and consisted in warming 3 cubic 

 centimeters of melted butter fat with an equal quantity of 

 glacial acetic acid in a test tube with agitation until complete 

 solution took jilace. The solution was allowed to cool while 

 being stirred with a thermometer and the temperature noted 

 at which the solution became turbid. Allen gives temperatures 

 of from 50° C. to 61.5° C. for pure butters. Our own temper- 

 atures, for some unexplained reason, were noticeably lower; 

 they are at least comparable. It will be noted that in the first 

 period Herd I. had a slightly lower turbidity point than Herd 

 II., showing, as have other tests, a slight difference in the com- 

 position of the butter fat. In the second period this difference 

 was more noticeable, and was very marked in the third or soy 

 bean oil period, amounting to nearly 12°. It would appear that 

 the higher the percentage of olein in the butter the higher was 

 the point of turbidity. Whether the excess of free fatty acids 

 had anything to do with the higher point of turbidity is un- 

 certain. - 



The refractive index on the various samples was made with a 

 water jacketed Abbe refractometer at 40° C, according to the 

 instructions given. Only in the third period in case of Herd II. 

 does one note a slight variation and increase over the fat pro- 

 duced in the other two periods. 



> Lewkowitsch, p. 862. s LewkowitBch, p. 218. 



