DAIRY FARMING DAIRYING. 787 



present. "In this respect the character of the enzym present conforms 

 closely to that of trypsin." Other experiments were made showing the 

 power of the enzym extract to liquefy gelatin. 



Tables are given showing the comparative rate of ripening in cheese 

 and in milk. "The progressive nature of the changes in both cheese 

 and milk are similar, the rate being somewhat more rapid in milk than 

 in cheese, a fact of some moment when it is considered that bacterial 

 activity was suspended in these milks." 



The effect of temperature on ripening was also studied, cheese being 

 kept at 55, 63, 73, and 86° F. The cheese kept at the higher tempera- 

 tures ripened faster, which "is in conformity with what is well known 

 concerning the action of enzyms under these conditions." A cheese 

 more than a year old which has been kept under chloroform from the 

 beginning, and, according to bacteriological examination, is perfectly 

 sterile, is said to be thoroughly broken down, resembling a well-cured 

 cheese. Chemical analysis shows that more than 50 per cent has been 

 converted into soluble products. A sample of milk to which both ether 

 and rennet were added after 4 months had 44.8 per cent of the total 

 protein of the curd converted into soluble products. Both the cheese 

 and the milk contained tyrosin and leucin like normal cured cheese. 

 These same products were found in samples of skim milk kept under 

 anaesthetic conditions for varying periods of time. 



The authors discuss the relation of these inherent milk enzyms to 

 current theories of cheese ripening and some other phenomena hitherto 

 difficult to explain. 



'•'It is our present belief that the ripening of hard cheese, instead of being due 

 solely to bacteria, is caused by the joint action of both organized (bacteria) and 

 unorganized ferments (enzyms). The breaking down of the casein is undoubtedly 

 due, in larger part, to the action of enzyms. Concerning the production of the char- 

 acteristic flavors, our knowledge is as yet too vague to warrant a definite assertion 

 as to their origin. In all probability the bacteria in this relation play a much more 

 important role." 



Influence of temperature on the ripening of cheese, S. M. Bab- 

 cock and H. L. Russell ( Wisconsin Sta. Rpt. 1897, pp. 194-210, Jigs. 

 7). — In the introduction the authors discuss the inadequate provision 

 for curing cheese in the large majority of cheese factories, and call 

 attention to the very deleterious effect of high temperatures on the 

 quality of cheese. A diagram is given showing the actual temperature 

 variation in an imperfectly constructed curing room in comparison with 

 the variation in the cheese cellars of the Wisconsin dairy school. The 

 zone which is stated to be invariably consistent with favorable results 

 extends from G5° F. downward. In the investigations on the effect of 

 temperature on the curing of cheese a special cheese-curing chamber 

 was made in which the temperature could be controlled and varied at 

 will by the use of ice or a gas burner, and another was made for lower 

 temperatures (cold storage). The construction of these chambers is 

 illustrated and described. 



