Sept. ii, 19x6 Progressive Oxidation of Cold-Storage Butter 933 



with the system B. F., etc. The stopcocks S 4 , K, and H are now all closed. 

 Water at a temperature of 45 ° C is poured into the glass jar surrounding 

 B. T. until it immerses the rubber stopper carrying the stopcock K and 

 the rubber connection between the small side tube to B. T. and H. The 

 warmth thus applied to the butter tube at once causes a slight pressure 

 against K and H. H is opened first to allow one or two trapped bubbles 

 of air to escape up toward B and is then closed. K is immediately opened 

 and is soon after followed by the opening of H again. As the material in 

 B. T. melts, a graduated and regulated opening of S 4 permits most of the 

 air confined within the sample to pass over into the system, and the 

 remaining air follows with the melted fat, etc., which passes up, around, 

 and down through e and trickles into B. F. A too rapid passing of butter 

 containing much curd should be prevented, as it will cause considerable 

 foaming in the butter flask. The warm salt solution flowing in from B 

 displaces the sample from B. T. When the material has been thus 

 removed from B. T. and the level of the salt solution has reached S 4 , 

 this stopcock is closed, followed also by the closing of S 3 . The gas is now 

 transferred from the apparatus by the Topler pump to the gas-collecting 

 tube G, allowing a few minutes to elapse between strokes of the pump, 

 thus permitting the gas containing moisture not removed by M. F. to 

 become dried by passing over or remaining in contact with the sulphuric 

 acid in c. The gas is collected over mercury in G and is drawn therefrom 

 into the mercury-filled measuring burette M. B. connected with the 

 leveling tube L. T., from which it is passed over into the Hempel pipettes 

 H. P., where the quantities of carbon dioxid and oxygen in the gas are 

 determined in the usual manner with solutions of potassium hydroxid 

 and alkaline pyrogallol. 



SPECIAL BUTTER TUBES 1 



These tubes are about 9 inches long and 1 z /i inches in diameter, with 

 necks widened somewhat to accommodate a No. 9 rubber stopper carry- 

 ing a glass stopcock. An ordinary-sized glass tube, bent on itself, leads 

 upward from the base. Each of these tubes when packed will contain 

 about 250 gm. of butter. 



These tubes were cleaned, sterilized, and packed with the sample, 

 allowing a very small air space between the surface of the butter and the 

 rubber stopper. Pure, neutral, paraffin oil was poured on the surface of 

 the butter and the stopper was pressed in until the oil in the tube had 

 risen above the stopcock. The stopper was wired down tightly and the 

 stopcock closed. A few cubic centimeters of paraffin oil were then 

 allowed to flow down the side tube. Butter packed in this manner is 

 free from contact with the outside air. 



1 The use of these tubes for packing and storing butter was suggested by Mr. L. A. Rogers, of the Dairy 

 Division. 



