Report oF New YorK AGRICULTURAL EXPERIMENT STATION. 153 
change taking place rapidly at first and then gradually. (3) Pro- 
teids in water-soluble form appear to increase only slightly, if at 
all, until after the salt-soluble proteid has partially changed into the 
form insoluble in salt solution. : 
4. Changes in calcium and phosphoric acid compounds of cheddar 
cheese — The calcium and phosphoric acid compounds of cheese, in- 
soluble at the start, become soluble, until about 80 per ct. of the 
calcium and all of the phosphates become soluble in water. This 
change is due to the formation of lactic acid and its action upon the 
phosphates of the cheese, resulting in the formation of monocalcium 
phosphate and calcium lactate. About 20 per ct. of all the calcium 
in the cheese is found in the salt-soluble portion, and the proteid 
in this solution shows an acidity about equal to that shown by cal- 
cium paracasein. 
5. The acidity of the water-extract of normal cheddar cheese is 
largely due, not to the presence of free lactic acid, but to monocal- 
cium phosphate. 
Il, SOME OF THE FIRST CHEMICAL CHANGES IN 
CREDOAK CHEESE: 
- In previous studies of the ripening changes in cheddar cheese 
made at this Station! it was shown that the calcium paracasein 
of the freshly coagulated milk undergoes various changes, most 
prominent among which is the formation of a substance soluble 
at 50° to 55° C. in 5 per ct. solution of sodium chloride. Most 
of the work formerly done was confined to an examination of 
cheese after it was taken from the press, generally about 24 
hours after the beginning of the operation of cheese-making or 
about 18 hours after putting in press. Little work was done in 
studying the intermediate period between putting the cheese in, 
and removing from, the press. 
While working upon camembert cheese, it was noticed by one 
of the authors that marked changes occur in the cheese proteids 
during the first 24 hours from the time of commencing the 
operation of cheese-making. ‘This fact naturally suggested that 
similar changes might occur in the early history of cheddar 
cheese during that period of time which had not been previously 
studied with care. It has been found that the changes taking 
place during this early period are of the same character and 
e 
*N. Y. Agrl. Exp. Sta. Buls. 214 and 261. 
