CHEESE MAKING. 363 



detached from tlie parent cell and go on increasing and 

 forming other cells which separa^te and increase to an in- 

 calculable extent. It is supposed by some chemists that 

 rennet is highly charged with these germs, and being a 

 nitrogenous substance they grow in it and increase with 

 amazing rapidity. When rennet is mixed with warm 

 milk these germs are carried all through the mass and 

 each one becomes a center of most active growth which 

 is encouraged by the heat. One effect of these germs is 

 to produce acidity, and doubtless they are able to cause 

 the coagulation of the milk and produce curd without 

 producing apparent acidity; perhaps because of the effect 

 of the coagulation being to neutralize as fast as it is pro- 

 duced any acidity which may be formed. We know, how- 

 ever, that acidity is only the work of time, and if it were 

 not prevented by cooling and salting and pressing the 

 cheese, by which moisture and air are expelled, the curd 

 would soon become acid, next ferment, then decay, 

 and finally putrefy. Putrefaction and destruction seem 

 to be the ends and purposes of these germs in nature, and 

 the whole art of the dairyman, from beginning to end, 

 is a conflict with these abounding spores, to prevent or 

 control their action and turn them to account m pro- 

 ducing such effects as he desires and prevent any further 

 action be3^ond that. 



The coagulation of the curd and its ripening, and the 

 curing of the cheese, are all results of the action of these 

 germs, aided by variations in temperature. And we can- 

 not doubt that they may be so used as to very greatly 

 affect the flavour of the cheese in its curing. This will be 

 more ^particularly referred to in describing the processes 

 by which the most highly valued kinds of cheese are 

 cured and caused to acquire a certain texture, condition, 

 and flavor. It is known that these fungi live and grow 

 and feed at the expense of the nitrogenous substance of 

 cheese, hence a cheese rich in caseine and poor in fat 



