vi] THE BACTERIA OF MILK 67 



the -^g-th of an ounce), the main portion of the niilk 

 about 5000, and that it was only the last 10 oz. drawn 

 that were practically free from bacteria. 



In view of what has been now stated, we may 

 affirm that milk, as usually obtained, contains micro- 

 organisms, and that these organisms will develop and 

 increase in milk, unless it is specially submitted to 

 the action of heat, or is treated with antiseptics. 



Importance of a Knowledge of Bacteriology to 

 the Farmer. Now, while bacteria may be regarded, 

 as far as milk itself is concerned, as undesirable, yet 

 we must remember that the manufacture of dairy 

 products, such as butter and cheese, are dependent on 

 their action ; so that a consideration of the subject is 

 doubly interesting to all engaged in dairying, not 

 merely on account of the harm they do in promoting 

 undesirable changes in milk, but also for the indis- 

 pensable role they perform in the manufacture of 

 butter and cheese. We should try to know, therefore, 

 as much about the nature of these minute organisms, 

 and about the conditions which influence their de- 

 velopment, as possible, so as to enable us to take 

 precautions either in checking or killing them, or in 

 regulating and fostering their development when 

 required. The success of the dairy industry depends 

 on properly controlling certain fermentative processes, 

 such as that potent in cream -souring for butter 

 manufacture, and that active in starting and develop- 



