THE RIPENING OF CHEESE. 237 



cannot as yet say. It is highly probable that the milk-sugar 

 generally, if not perhaps entirely, directly causes the formation of 

 all the pores in the cheese, the small and very numerous holes in 

 the American, English, Dutch, and other hard cheeses, as well as the 

 holes about the size of beans which are unconnected but regularly 

 distributed in the Emmenthaler. 



The fat is very little affected to all appearance by the decom- 

 positions going on in the ripening cheese mass. At any rate, in no 

 case do the products of fat decomposition exercise a noticeable 

 influence on the characteristic properties of the different kinds of 

 cheese. Probably the only influence which the fat exerts on the 

 characteristic nature of the cheese is in affecting its pleasant flavour, 

 and the tenderness and softness of the cheese. These properties de- 

 pend on the quantity of fat present. It is not impossible that the fat 

 hinders and retards, according to the amount in which it is present 

 in fat cheeses, the action of the albumin bacteria on the paracasein. 



Of mineral constituents of the cheese, a portion, especially lime 

 and phosphoric acid, are lost by passing away with the salt, in the 

 salting of the cheese, by the process of osmosis. Whether, and to 

 what extent, the mineral salts are directly or indirectly split up by 

 the growth of bacteria in the ripening processes, is not known. 



The percentage of water in the cheese becomes distinctly less 

 during ripening.. A portion of the water evaporates or flows away 

 in the salting of the cheese with the salt solution, and another 

 portion is lost by the water forming in the ripening process new 

 combinations, and entering into chemical combination. 



The slowly-ripening hard cheeses do not appear, during the 

 ripening process, to suffer any appreciable further loss of weight, 

 unless by that due to loss of moisture. Up till now, at least, it has 

 not been discovered that any loss of the volatile ammonia salts, 

 volatile fatty acids, or methylamine occurs. On the other hand, 

 it is highly probable that the rapidly-ripening soft cheeses, posses- 

 sing a penetrating odour, suffer a loss of their organic substance. 

 What constituents of the cheese are decomposed in these losses, and 

 in what way the loss takes place, is not yet known. It has also not 

 yet been demonstrated with certainty that there is a development 

 of small quantities of indol and skatol in the ripening of cheeses 

 possessing an odour, nor has it been ascertained whence the free 

 butyric acid is derived, which it has been proved is invariably 

 present in ripening cheeses, arid which is present, in large quantities, 



