210 MODERN" DAIRY PRACTICE. 



taining sweet milk.* Thanks to this manner of procedure, 

 the souring took place more rapidly. 



In the unconscious infection of fermentation-starters, 

 the cause usually lies in the fact that the milk-pans used 

 for creaming have not been sufficiently cleaned. The 

 result, however, in this case must evidently be more un- 

 certain. Strange to say, we rarely find other than lactic- 

 acid bacteria in excessive numbers in sour milk at our 

 farms. The reason is doubtless that these bacteria are not 

 checked as strongly in their development as others, the 

 milk-pans being placed outdoors in the sun, dried and 

 aired, to which treatment the putrefactive bacteria are 

 very especially sensitive. If the pans be thoroughly sun- 

 baked they become wholly sterile, as we saw before, and 

 the souring of the milk has then to be started by inocula- 

 tion with sour milk. 



The inoculated milk is mixed with all kinds of bacteria, 

 and the ripening is not therefore always successful. One 

 result of this fact is that farm butter is so much poorer 

 in winter, when milk is produced in the stable. Com- 

 paratively good pure cultures may, however, be obtained 

 under the primitive conditions present in the manufac- 

 ture of farm butter. If an effort is made to improve 

 these conditions by introducing greater cleanliness in 

 stable and dairy, and by increasing the knowledge of the 

 principles of dairying among farmers, the result ought to 

 be still better. If, for instance, the milk is pasteurized 

 before being creamed, we should soon find that the souring 

 will always take place in a proper manner also in the 

 shallow setting system. 



* At farms in Norway this inoculation is often effected by plac- 

 ing a little pure sour milk at the bottom of the milk-pans. W. 



