140 MILK AND DAIRY PRODUCTS PART 



to fill the tube to the upper mark. It is better to take too 

 much rather than too little benzine. The tube, &, is now taken 

 from the cylinder, a, the latter filled with water at 55 to 

 within 4 cm. of the upper edge, and the tube replaced. 

 After the butter has melted, the protein is seen to have 

 separated in a very voluminous form, the paper is withdrawn, 

 and the stopper put into place. The tube, b, along with the 

 wooden stopper, c, is lifted from the cylinder and the rubber 

 stopper pressed in with the flat of the hand. The apparatus is 

 then inverted, so that the large stopper is below, and the 

 contents thoroughly mixed by vigorous shaking. Afterwards 

 the tube, 5, is returned to a, and the apparatus left to stand 

 for four hours. During this time the non-fatty substances 

 separate completely, leaving a sharp dividing line below the 

 protein layer and the solution of fat. When the temperature 

 of the water in a has reached that of the room, and not before, 

 the percentage of fat is read off on the graduated scale. 



It has been shown by A. Hesse l and by the author that this 

 method gives results which only in exceptional cases differ by 

 1 per cent, from those obtained by gravimetric analysis. For 

 all practical purposes such results are sufficiently accurate. 



III. DETERMINATION OF THE ANHYDEOUS SOLIDS NOT FAT. 



In addition to fat and water, there are found in butter small 

 quantities of protein, milk-sugar and other nitrogen-free 

 substances (lactic acid), arid also mineral matter. When the 

 butter has been salted there is also common salt. 



An estimation of the total amount of these substances 

 is made in the following manner : Five to 10 g. of butter (with 

 unsalted butter 10-15 g.) are weighed out into a small glass 

 beaker, or better into a glass dish with spout, of about 10 cm. 

 diameter. The butter is then melted at a low temperature, 

 some petroleum ether added, and the mixture filtered through 

 a Swedish filter that has previously been dried and weighed. 

 As far as possible the sediment should be left in the dish. 

 Further treatment with petroleum ether and subsequent 

 decantation through the filter free the sediment from the 

 greater part of the fat. The mass should not, however, 

 1 Molkerei-Zeitung, Hildesheim, 1905 No. 41. 



