LIME AND MILK. 267 



fore in case][of a deficiency in lime, the coagulum will contain a 

 larger proportion of precipitated casein. The ripening process is 

 considerably accelerated but the cheese yield will be lower, curds 

 deficient in lime will be much softer, not so " firm " as ordinary 

 curds. 



Professor Lloyd advises providing cattle with drinking water 

 rich in lime to prevent such deficiency, but this is not sufficient in 

 all cases. A deficiency can be obviated in three ways : — 



1. By adding a soluble lime salt to the milk before renneting. 



This is the cheapest but at the same time the most hazard- 

 ous course. The balance of the milk is artificially upset 

 and the composition " improved " in one direction. 

 Frequently difficulties arise in the ripening process which 

 may become abnormal. 



2. By feeding a lime salt to the cattle either by mixing it with 



the food or by providing a salt lick containing lime. 

 This is an improvement on the first-mentioned method 

 as now the deficiency of lime is made up in the body of 

 the animal ; but the best method is : 



3. To apply a lime fertiliser to the land. This will ensure an 



improved richness in the lime in the grazing and the 

 animal receives the lime in a more assimilable condition. 



In the process of butter-making lime plays a less conspicuous 

 role. Its influence is noticeable chiefly in the maturing of the 

 cream. This maturing is due to the activity of two different 

 species of bacteria, peptonising germs and lactic acid germs. 



Matured cream should have a slimy appearance, somewhat 

 resembling a custard. This slimy consistency is the work of 

 the peptonising bacteria. A certain quantity of lactic acid is 

 developed at the same time as this improves the flavour of the 

 butter. If a deficiency of lime occurs, the lactic acid forming, 

 will, instead of combining with lime, at once begin to act on the 

 casein and precipitate it. The peptonising germs produce a 

 chymosine-like ferment, which coagulates the casein, but once 

 it has been precipitated, the casein can no longer be precipitated 

 by this chymosine. 



This little sketch would not be complete if I did not show the 

 uncertainty that still exists on certain points about the role, lime 

 plays in dairying. This year Mr. W. van Dam published in the 

 Reports of the (Netherlands) Government Experimental Stations 

 some investigations of curdling. The purpose was to investigate 

 the cause why some milk refuses to coagulate, a phenomenon 

 hitherto ascribed to deficiency in soluble lime salts. Mr. van 

 Dam's conclusions differ widely from the opinions of well known 

 authorities, but since the establishment of the dissociation theory 

 and the discovery of the radio-active bodies, our conceptions 

 of chemistry are undergoing such fundamental changes that a 

 clashing with old accepted theories does not any longer warrant 

 the simple rejection of a contradictory theory. Mr. van Dam 

 states that a distinction must be made between the potential 

 degree of acidity as found with the acidimeter and the absolute 



