262 AGRICULTURAL BACTERIOLOGY. 



at once, highly flavored as it is by the joint action of molds 

 and bacteria. 



The different types of soft cheeses are of course handled 

 differently. Some are made from whole milk, some from skim 

 milk, some from sheep's milk and others from goat's milk. 

 Some are slightly salted. Some are more completely deprived 

 of liquid than others. Some are treated in such a way as to 

 prevent the growth of molds, others in such a way as to stimu- 

 late such growth. Different temperatures are employed at 

 different stages, and sometimes three ripening chambers, with 

 different temperatures, are employed. All of these differences 

 make the varieties which we find in the types of soft cheeses. 

 In addition to all this it is quite sure that different species of 

 bacteria and molds are concerned in the ripening of the various 

 kinds of cheese. 



The details of these various processes are not yet under- 

 stood in any single case. Of the nature of the flavoring prod- 

 ucts we are ignorant, but that they are, in large measure at 

 least, if not wholly, due to the growth of microorganisms 

 cannot be questioned. At present we know almost nothing 

 concerning the species of bacteria which contribute to the 

 ripening, nor do we know whether the different types of flavors 

 are due chiefly to different species of microorganisms or to the 

 same organisms acting under different conditions. We must 

 in short at present be contented with the conclusion that the 

 different flavors of the soft cheeses are due to different types 

 of decomposition produced by microorganisms. 



Hard Cheeses. The ripening of hard cheeses is even less 

 understood than that of soft cheeses. The ripening is in gen- 

 eral similar to that of the soft cheeses but it takes place much 

 more slowly, several weeks, or even months, being frequently re- 

 quired to complete it. The final result is quite different from that 

 of a soft cheese and is plainly due to a different sort of decompo- 

 sition, as is indicated by the totally different flavors developed. 



