New York Agricultural Experiment Station. 167 

 INTRODUCTION. 



In 1880 Babcock^ carried 011 some experiments in cheese- 

 curing, in which he attempted to measure the amount of carbon 

 dioxide formed by cheese in ripening; but his study of each 

 cheese was Hmited to short periods of time and the source of the 

 carbon dioxide formed was not ascertained by him. The in- 

 vestigation described in this bulletin was undertaken prmiarily 

 to learn to what extent carbon dioxide is given ofif by American 

 cheddar cheese during long periods of time in the process of 

 ripening. It was hoped that by such study we should be able 

 also to learn the sources of the carbon dioxide thus formed and 

 add to our knowledge in regard to some of the deep-seated 

 chemical changes occurring in the ripening of cheddar cheese. 



As material for use in carrying on the investigation, we made 

 two cheeses. One was normal in every respect; the other was 

 made from milk containing chloroform and was kept under anti- 

 septic conditions, thus enabling us to suppress factors of biolo- 

 gical activity. The study was continued for 32 weeks, at the end 

 of which time we completed the work by making a study of 

 the end-products in each cheese, including, more particularly, 

 diamido compounds and their secondary cleavage products and 



tyrosine. 



EXPERIMENTAL PART. 



preparation of cheese. 



For each cheese we used about 20 kgs. (45 pounds) of milk 



that had been drawn from the cows' udders not more than three 



hours. One cheese was made in the usual manner, being normal 



in every respect. In making the other cheese, we added to the 



milk at the start 4 per ct. by volume of chloroform and then 



enough lactic acid to equal 0.2 per ct. of the milk by weight. 



The rest of the process of cheese-making was carried on in the 



usual way. In both cases salt was added at the rate of i part 



for 400 parts of milk used. The normal cheese weighed 6 



pounds and 10 ounces (3000 grams); the cheese coutaining 



chloroform weighed 7 pounds and i ounce (3203 grams), owing 



to the retention of chloroform and more water. 



I Cornell Univ. Exp. Sta. Report, pp. 9-27 (1879-80). 



