66 AGRICULTURAL EXPERIMENT STATION. [Jan. 



Method of Milk Analysis. 



Total Solids. — Evaporate a known quantity of milk 

 (approximately 5 grams) in a weighed porcelain dish, con- 

 taining 15 to 20 grams of pure, dry sand, on the water bath 

 until apparently dry, then transfer to the air bath and dry 

 at 100° to 105° C. to a constant weight, weighing at intervals 

 of about an hour. In case of cream, use 2.5 to 3 grams for 

 evaporation . 



Fat. — Pulverize the sand containing the solids without 

 removing from the dish, subsequently transfer to a filter, 

 and exhaust with anhydrous, alcohol-free ether. Dry the 

 fat obtained on the evaporation of the ether in an air bath at 

 100° to 105° C. to a constant weight. 



Ash. — A weighed quantity of milk is evaporated to dry- 

 ness with a few drops of nitric acid, and burned in a muffle 

 at a low red heat until free from carbon. 



Metliods of Butter Analysis. 



( 1 ) Moisture. — Two and five-tenths to 3 grams are dried 

 at 100° C. in an air bath. 



(2) Salt. — Six to 7 grams of the butter are washed into a 

 separatory funnel with hot water, and are well shaken, and 

 allowed to stand until the fat has collected on top ; the 

 water is then drawn off, and a fresh quantity added, and 

 shaken up with the butter. This is continued until 200 to 

 300 cubic centimetres of water have passed through the 

 funnel. The washings are mixed, and made up to 500 cubic 

 centimetres, and the chlorine determined in an aliquot part by 

 means of silver nitrate. From the chlorine the salt is readily 

 calculated. 



( 3 ) Fat. — Two and five-tenths to 3 grams of the fat freed 

 from salt l)y the above operation (2), and from water by 

 drying in the air l)ath, are dissolved in ether, and filtered 

 from the curd into a tared flask. The ether is driven ofi', 

 and the residual fat dried and weighed. In calculating the 

 per cent., allowance is made for salt and water removed. 



(4) Casein. — The residue remaining on the filter in (3) 

 is tested for nitrogen by the Kjeldahl method. The fjictor 6.33 

 is used in reducing tlje per cent, of nitrogen fi)und to casein. 



