132 EXPERIMENT STATION. [Jan. 



STABILITY OF BUTTER-FAT SAMPLES.^ 



BY E. B. HOLLAND, M.SC. 



In the examination of butter fat, the question of stability is 

 one of prime importance. Should appreciable changes take 

 place in the samples, results would be vitiated and deductions 

 as to the effect of feed would be of questionable value. That 

 oils and fats are readily acted upon by a number of agents has 

 been long recognized, but whether butter-fat samples as ordi- 

 narily treated would be sufficiently changed as to affect analytical 

 results is uncertain, though quite probable from the nature of the 

 substance. To secure definite information on the subject it was 

 necessary to carry out several experiments, of which a descrip- 

 tion with data follows. 



The object of the first experiment was to determine the action 

 of air, light and moisture, respectively, at the same temperature, 

 upon butter fat. Heat as an independent factor could not be 

 studied at that time as it would have increased the work to a 

 point beyond which it could have been handled, ])ut the action 

 of heat was noted more particularly in another experiment. 

 About ten pounds of butter fat were prepared by melting 

 fresh butter and filtering the supernatant fat through paper 

 in a jacketed funnel. Two-ounce bottles, 73 in number, were 

 filled with the melted fat and placed in the north window of 

 the station creamery building in March, 1908. These bottles 

 were divided into seven sets, four of which were closed with a 

 glass stopper and sealed with ceresin to practically eliminate the 

 oxidizing action of the air, and the remainder simply protected 

 by a single thickness of unbleached cotton cloth tied over the 

 top, which readily permitted circulation of the air. One set of 



* This work was undertaken jointly with Dr. R. D. MacLaurin, but owing to the resignation 

 of Dr. MacLaurin it has been completed and prepared for publication by Mr. Holland. 



