422 Bacteria in Relation to Country Life 



cheese and the production of lactic acid by them ex- 

 cludes the predominance of other species. Moreover, 

 it would seem that the lactic acid thus produced unites 

 with the' casein (paracasein), forming thereby a com- 

 pound, which, there is reason to think, behaves differ- 

 ently towards the galactase and pepsin than does the 

 casein (paracasein) itself. In some of the experiments on 

 cheese-ripening the curd was prepared from pasteurized 

 or sterilized milk in which the galactase and pepsin 

 had been destroyed by heating. The enzymes being 

 thus excluded, the subsequent inoculation with lactic- 

 acid bacteria did not reestablish normal conditions. 

 In other experiments, on the contrary, the bacteria, 

 but not the galactase and pepsin, were excluded, lactic 

 acid was not formed, chemical reaction between the 

 casein (paracasein) and lactic acid did not occur, and 

 enzyme action was unquestionably modified thereby. 

 It will be seen, therefore, that the question is still far 

 from being settled. The indirect importance of the lac- 

 tic-acid bacteria in cheese-ripening having been estab- 

 lished, it remains for future experiments either to con- 

 firm the belief as to their direct action, held by many, 

 or to prove it untenable. 



Soft cheeses. The soft cheeses include Roquefort, 

 Camembert, Limburger, Stilton, Brie, Gorgonzola, 

 Backstein, Gammelost, Port de Salut, and others with 

 reputations more or less local. They differ from the 

 hard cheeses both in their method of preparation and 

 their appearance, taste and flavor. They are not sub- 

 jected to pressure, the whey is not as completely removed, 

 and they contain, in consequence, more moisture. Air 



