96 BOARD OF AGRICULTURE. 



to the dairy, — having before us pure milk in clean vessels, the next 

 points are, the degree of acidity, and the temperature at which it 

 should be set, i. e. the rennet added to it. 



When milk is drawn from the cow it is sometimes alkaline, 

 sometimes neutral, and sometimes acid, oftentimes in summer ; 

 never acid so as to taste sour, but sufficiently so to exhibit an acid 

 reaction to a delicate test.* As soon as exposed to the air there 

 commences a spontaneous conversion of the sugar (of which milk 

 usually contains from four to five per cent.) into lactic acid. The' 

 chemical composition of these two substances, as determined by 

 analysis, is the same ; yet they are very different substances, to 

 our senses of sight and taste, and the difference is supposed to be 

 due to a transposition of the elementary atoms of the sugar. 



Some hold that cheese is best made from new milk. It is true 

 that when too much changed only a hard, sour cheese can be made 

 from it. It is also true that those cheeses which bear the highest 

 reputation and command the highest prices, both in this country 

 and in Europe, are not made wholly from new milk, but from 

 evening's and morning's milk mixed. From all the evidence pre- 

 sented, I entertain no doubt that the latter is the better practice ; 

 or in other words, that it is desirable that the conversion of milk 

 sugar into lactic acid should have made some progress. The pre- 

 cise degree of progress which is best is not definitely known, nor 

 have we at present any easy method of measuring it with precision, 

 but practically it is found that if milk be kept for twelve hours at a 

 temperature of about 65°, and the morning's milk be then added, 

 and the whole properly warmed, the best results follow, and the 

 due separation of the whey is more easily effected. 



In the Cheddar method, which from its advantages both in the 

 saving of labor and superiority of product, is rapidly displacing 

 older methods of cheese-making in England, sour whey is usually 

 added, but this is unnecessary in this country, at least in most 

 cases during the summer months, because of the higher tempera- 

 ture which here prevails, which insures more rapid progress to- 

 wards acidity, and more caution is required that it do not progress 

 too far than not far enough. Mr. McAdam, a skillful practitioner 



* Litmus paper is used for this purpose. It is colored blue by a vegetable infusion. 

 A very slij^ht degree of free acid in any liquid is detected by the reddening of the 

 paper, and when thus reddened, a very little alkali sufifices to restore the blue. 



