628 MILK 



taken with sterile cheese samplers or cheese triers. For com- 

 posite samples each portion of the cheese should be represented. 

 Before making plates the sample is emulsified in sterile physiologic 

 salt solution. 



For chemical examination of cheese a wedge-shaped piece is 

 cut from the outside to the center. This is passed three times 

 through a sausage-grinding machine. When the cheese cannot 

 be cut, samples are taken with a cheese trier. Several plugs are 

 taken and mixed. 



Determination of Moisture. — Mix 2 to 5 grams of the mixed 

 sample with some porous material and heat in a water oven for 

 ten hours. 



Determination of Ash. — Determine the same way as in butter. 



Determination of Nitrogen Compounds. — Follow the procedure 

 used for milk. 



Determination of Fat. — The fat can be conveniently deter- 

 mined by the Babcock method. Weigh 6 grams of the sample in 

 a tared dish and add 10 c.c. boiling water, with a few drops of 

 ammonia. Stir the mixture until a perfect emulsion has been 

 formed. Add one-half of the usual amount of sulphuric acid and 

 transfer to a Babcock bottle. The other half of the sulphuric 

 acid is used for washing out the beaker. Then proceed as with 

 milk. Multiply the reading by 18 and divide by the weight of 

 the sample to obtain the percentage of fat. 



BIBLIOGRAPHY 



Ayers: United States Dept. of Agri., B. A. I., 1911, 28th Annual Report, 

 p. 225. 



Babcock, Farrington, and Hart: Univ. of Wis. Agri. Exper. Sta., Bull. 197, 

 July, 1910. 



Clark: United States Dept. of Agri., B. A. I., BuU. 151, September, 1912. 



Cohn : Beitrage zur Biologie der Pflanzen, 1872, Band 1, Heft 2, p. 127. 



Conn, Thorn, Bosworth, Stocking, and Issajeff: Storrs' Agri. Exper. Sta., 

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Currie: Jour. Agri. Res., 1914, vol. 2, No. 1. 



Dahlberg: United States Dept. of Agri., B. A. I., Bull. 576, September, 1917. 



Doane and Eldredge: United States Dept. of Agri., B. A. I., Bull. 148, March, 

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Doane and Lawson: United States Dept. of Agri., B. A. I., BuH. 146, De- 

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Dox: United States Dept. of Agri., B. A. I., Bull. 109, November, 1908. 



Eldredge and Rogers: Cent. f. Bakt., Abt. 2, 1914, vol. 40, p. 5. 



Esten and Mason: Storrs' Agri. Exper. Sta., Bull. 83, September, 1915. 



Evans, Hastmgs, and Hart: Jour. Agri. Res., 1914, vol. 2, p. 167. 



Hammer: Agri. Exper. Sta. Iowa State Coll. of Agri. and Mech. Arts, Re- 

 search Bull. 27, January, 1916. 



Harding and Prucha: New York Agri. Exper. Sta., Tech. Bull. 8, p. 121. 



Hardmg, Rogers, and Smith: New York Agri. Exper. Sta., Bull. 183, De- 

 oember, 1900. 



Harrison and Connel: Cent. f. Bakt., 1903-4, Abt. 2, vol. 11, p. 640. 



Hart, Hastings, Flint, and Evans: Jour. Agri. Res., 1914, vol. 2, p. 193. 



