170 



Dairy Bacteriology. 



ill. Gaseous fermentations in Swiss cheese. 



From the researches of v. Freudenreich, Baumann, and 

 Weigmann, it is known that certain gas-producing forms 

 invariably play a role in the normal ripening of Einmen- 

 thaler cheese. Sometimes Swiss cheese is devoid of 

 these gas holes, or " eyes," in which case, they are said 

 to be "blind." Such cheese may ripen well but their 

 market value is diminished on account of the absence of 

 these round holes. 



The size of the gas holes as they appear in abnormal 

 cheese is by no means constant. Neither is the character 

 of the hole dependent upon any specific germ. If the 

 gas-forming bacteria are plenty and quite evenly dis- 

 tributed the holes will be small and numerous as in 



FIG. 35. A block Swiss cheese, showing " gassy " fermentation. 



nissler ' ' cheese. Where the organisms are less frequent 

 and develop in small groups, then the " eyes" are much 

 enlarged. As the different organisms vary in their in- 

 tensity of gas formation, this too, modifies the size of the 

 gas holes to a marked degree. 



