218 Milk Inspection. 



of wine for the determination of sugar, and kept for 2 hours in 

 an incubator, and after this period the amount of oxygen formed 

 during this time is measured. It should not exceed more than 

 about 1 c. c. 



Apparatuses which indicate the total amount of gas formed 

 are more suitable; for instance, the "Catalaser" constructed by 

 Henkel, or still better the one by Lobeck, in which a gas collecting 

 and measuring tube is so attached above the bulb containing the 

 milk that a fine gas tube leading from the bulb to the upper part 

 of the gas measuring apparatus allows the exit of the oxygen at the 

 point. At the bottom of the gas collecting tube another tube 

 opens, through which the water contained in the measuring tube 

 is displaced by the liberated oxygen. Faitelowitz has constructed 

 a shaking apparatus and a special "Catalaser"; the shaking is 

 supposed to expedite the liberation of the oxygen. 



Fresh milk evolves 1 to 2 c. c. of oxygen. Eaw or pasteurized 

 milk, spoiled through invasion of bacteria, produces considerably 

 larger amounts of oxygen; likewise milk rich in cellular elements 

 as a result of physiological or pathological irritations of the udder, 

 or mixed milk polluted by such secretions. The test is useless for 

 the examination of market milk as to the presence of inflammations 

 of the udder. 



High oxygen values of the catalase test in connection with low 

 reductase values against the watery methylene blue, create a sus- 

 picion of mastitis. 



High values by both methods indicate principally a spoiled 

 condition, without differential diagnostic value relative to inflam- 

 mation of the udder or bacterial decomposition. If the testing of 

 the milk indicates that the product was pasteurized, sterilized or 

 otherwise heated, and the catalase test is positive, the generation 

 of oxygen proves the spoiled condition of the milk as a result of 

 bacterial decomposition. 



With fresh individual samples and samples from individual 

 quarters the increased value of catalase proves the presence of 

 mastitis, provided that no severe general diseases are present, and 

 provided physiological irritating conditions are excluded. If all 

 samples from the 4 quarters show increased catalase values, mas- 

 titis may be present in all 4 quarters, or there may exist a general 

 disease, as for instance tuberculosis or peritonitis. 



The test for amylase is only applicable to raw milk. Into each 

 of ten test tubes are placed 10 c. c. of milk and . 1, . 2 up to 1 c. c. 

 of a 1% solution of soluble starch which is dissolved through heat- 

 ing. The series of tubes are placed for half an hour in the incu- 

 bator. Then they are rapidly cooled, and to each is added 1 c. c. of 

 a solution of iodine and iodide of potassium (1 of iodine, 2 of iodide 

 of potassium, 300 of water). If the total amount of starch has 

 been converted into sugar, the color of the mixture will be yellow. 

 A grayish-yellow with a grayish-blue tinge indicates unchanged 



