DAIRY FARMING DAIRYING. 585 



Concerning the amount of lime salts to be added, it was found that 

 the largest increase was obtained with the addition of 0.01 per cent of 

 calcium oxid to the milk, which is equivalent to 4.") gin. of monocalcium 

 phosphate, or 20 gin. of calcium chlorid, per 100 kg. of milk. The 

 increase with lime salts disappears when the amount of rennet is cor- 

 respondingly diminished. The value of the increase is placed at 2.}cts. 

 per 100 kg. of milk for skim cheese and 8£ cts. per 100 kg. of milk for 

 Emmenthaler cheese. On account of the higher price of monocalcium 

 phosphate the author recommends the use of calcium chlorid in the 

 case of skim cheese. 



The author wishes his results to be regarded as preliminary and 

 strongly urges that cheese factories make practical trials of the 

 method. He gives detailed directions for the method of using the lime 

 salts. The proper amount of lime salts is dissolved in about 1 liter of 

 water and the solution added to the milk before adding the rennet. 

 It is recommended to use larger amounts of salts in the milk of cows 

 well advanced. As to the amount of lime to be added, the equivalent 

 of 10 to 20 gm. of calcium oxid per 100 kg. of milk is recommended, 

 and a table is given showing the amount of calcium oxid corresponding 

 to different amounts of monocalcium phosphate and calcium chlorid. 



It is suggested that the addition of lime may also be beneficial in 

 working with milk which has been pasteurized at a high temperature 

 and hence curdles less completely with rennet. Laboratory experi- 

 ments in heating milk for 3 to 5 minutes at 85 to 90° with the addition 

 of lime salts have shown that such milk curdle 1 as well as before heat- 

 ing. By adding some sour milk prepared with pure cultures to such 

 pasteurized milk it can be rendered suitable for cheese making. 



On the cause of ripening of Emmenthaler cheese, E. von 

 Freudknreich (Centbl. Bait. u. Par., 2. AM., 7 [1897), Nos. 9-10, pp. 

 231-235; 13-14, pp. 349-351). — The author made experiments with 

 tyrothrix, which is believed by Duclaux to be the chief cause of the 

 ripening of cheese. Large quantities of these bacilli were introduced 

 into the curd, but in a number of the experiments it was found that 

 they rapidly disappeared as the cheese ripened. 



The author next attempted to demonstrate the accuracy of his theory 

 that the change in the casein in ripening cheese is due to lactic acid 

 bacteria. He made experiments in skim milk with 3 different kinds 

 of lactic acid bacteria. To determine the change in the casein the 

 nitrogen found in portions of the cultures filtered through a porcelain 

 filter was compared with the nitrogen in the filtrate from the control 

 milk to which no culture was added. It was found in this way that 

 culture A contained 2.1 times as much soluble proteids as the control 

 milk, culture B G.4 times, and culture C 5.1 times. This, the author 

 states, shows that beyond doubt a part of the casein in the cultures B 

 and C was changed to a soluble form. It was found that adding 0.5, 

 1, and 2 per cent of lactic acid to milk did not cause any perceptible 



