in CHEESE 187 



2. The Schmid-Bondzynsld Method. 1 



This method, which was originally designed for milk, has 

 only found application to any extent in the estimation of fat in 

 cheese. RatzlafFs 2 modification, which is a combination of the 

 Schmid-Bondzynski and the Rose-Gottlieb methods, is prefer- 

 able to the original. 



Three to five grams of cheese are weighed into a 30 c.c. flask 

 and 10 c.c. of HC1 (sp. gr. T125) added. The flask is then 

 warmed on an asbestos plate over the free flame until the cheese 

 dissolves, and afterwards for 8-10 minutes at boiling point. After 

 cooling, the solution, which now ought to have a reddish-brown 

 colour with a layer of fat on the surface, is transferred to a 

 Gottlieb cylinder which is graduated the whole length. The flask 

 is washed with ether from a small wash-bottle, and the washings 

 transferred to the cylinder, 25 c.c. of ether being used in all. The 

 cylinder is corked up, well mixed, and then 25 c.c. of petroleum 

 ether (b. p. below 70 C.) added. After the cylinder has 

 been again well shaken, it must be allowed to stand for at 

 least two hours, and in that time the ethereal solution separates 

 sharply from the cloudy layer below, so that it can easily be 

 syphoned off into a tared flask, leaving only 1*5-2 c.c. behind. 

 The ether may then be evaporated, as Ratzlaff advises, the fat 

 weighed, and the total amount calculated from the proportion 

 of the whole of the ethereal solution to that part which was 

 syphoned off. To do away with this calculation, Siegfeld 3 adds 

 another 25 c.c. ether and petroleum, shakes up again, and then 

 syphons off the ethereal solution, when it has separated, into 

 the same flask, and this gives the total fat in the cheese. 



3. Rose-Gottlieb Method. 



This excellent method for the determination of fat has 

 recently been modified by Palmquist, 4 and made quite suitable 

 for the estimation of fat in cheese. 



About 1 gram of cheese, which has been finely divided and 



1 Chemisches Ceniralblatt, Vol. I, p. 447. 



2 Milch-Zeitung, 1903. 



; Mi/ch-Zeituny, 1904, No. 19. 



4 Svensk. Kern. Tidtkr., 1905, p. 58, 



