170 ALLUSION TO THE MAKING OF CHEESB. 



from the milk sugar. The appearance which the curd 

 of milk, or the casein presents, when curdled either 

 by rennet or an acid, is so well known as to render 

 any description unnecessary. 



a. In the analyses of the ash from milk. Table xi., 

 was mentioned a small quantity of free soda. This 

 being dissolved in milk, keeps the casein likewise m 

 solution; but when any of the acid substances men- 

 tioned above are added, they immediately unite with 

 and neutralize the soda; the liquid then of course be- 

 comes acid, so that the curd falls down at once. Ren- 

 net is not supposed to do this by acting as an acid, 

 but by promoting the formation of an acid in the milk 

 itself, which does the work. The milk is thus made 

 to curdle by the action of its own acid. 



This is not the place to enlarge upon the practical 

 methods of cheese-making, nor upon the endless va- 

 rieties of cheeses to be found in this and other coun- 

 tries. Scarcely any two districts have a similar prac- 

 tice in their manufacture, or produce an article at all 

 identical in its taste or appearance. Those of some 

 districts would be considered the reverse of excellent 

 in others. For instance, a variety most highly valued 

 in Paris, has undergone an incipient putrefaction, so as 

 to evolve ammonia. _ i i ♦ 



The richest cheeses are made by adding the last 

 night's cream to the morning's milk. Such are the 

 Stilton cheeses of England; from these we have them 

 all the way down to skim milk, and, in some counties 

 of F.no-land, to those which are made from milk that 

 has been skimmed for three or four days in succession. 

 Such as these are perfectly hard and horny. fhe 

 following table from Prof. Johnston's lectures, gives 

 the composition of several English and Scotch va- 

 rieties of cheese. 



