240 SCIENCE AND PRACTICE OF DAIRYING. 



opening up a new point of view, and they have pointed to the way 

 along which light on the process of the ripening of cheeses will be 

 gradually obtained. This way lies in the closely intimate relation 

 that exists between the investigations of bacteriology and chemistry. 

 To begin with, systematic attempts have been made to discover by 

 means of these two sciences what kind of bacteria are at work and 

 in what way the chief phenomena are brought about, as, for ex- 

 ample, the change of paracasein, the change of milk-sugar, and the 

 formation of holes in the cheese; also what effect bacteria and the 

 lower forms of fungoids have on the fat, &c. It may perhaps be 

 soon proved that the processes taking place in the ripening of 

 cheese are neither so complicated in degree, nor so many-sided, as 

 we are at present inclined to think. 



The functions performed by the lower fungoids in the manu- 

 facture of cheese have been previously discussed in 43. As has 

 already been mentioned, it must be assumed that milk universally 

 and invariably contains all the different kinds of bacteria which act 

 in the manufacture of cheese. It has also been already pointed 

 out that fresh curd resembles to a certain extent a field which is 

 richly sown with the most varied kinds of bacteria, but on which 

 no kind of bacterial vegetation is permitted at that stage to pre- 

 dominate. If it be observed that the milk of individual cows, or 

 the milk of a whole herd, has proved itself useless for the manufac- 

 ture of cheese, since, when utilized for this purpose, even with the 

 observance of the greatest care and with the most intelligent work, 

 certain phenomena of ripening take place prematurely or in a 

 disturbing manner, or the flavour of the cheese is unpleasant, 

 or there is any other failing manifested, the author is inclined 

 to believe that this does not, as a rule, arise from the fact that the 

 milk has become contaminated with peculiar bacteria not generally 

 present. Such phenomena are probably rather to be traced in most 

 cases to the fact that some of the common sorts of bacteria of milk 

 have developed with special luxuriance, and have changed the 

 properties of the milk to a certain extent, a state of matters which 

 has adversely influenced the development of the other common 

 kinds, and has given the ripening process an undesirable direction. 

 It must not, however, be denied that occasionally strange kinds of 

 bacteria, which have nothing to do with the ripening of cheese, find 

 their way into the milk, and are thus able to disturb the manufac- 

 ture of the cheese. Milk, when it is coagulated, ought not, as a 



