168 MODERN DAIEY PEACTICE. 



household utensils. This is in my opinion the great 

 secret and the main reason why farm butter can be first- 

 class and of good keeping quality during the summer-time, 

 in spite of many unfavorable conditions and poor facili- 

 ties. As previously shown sun rays in a short time kill 

 all bacteria. The putrefactive butyric acid and similar 

 darkness-loving bacteria seem to be easily destroyed by 

 direct sunlight. The lactic-acid bacteria are also sensitive 

 to their action, but according to my experiments are not 

 so easily killed in sunlight as the former. The presence of 

 lactic-acid bacteria in the milk-pans is not, however, as 

 injurious for the milk as that of putrefactive and butyric- 

 acid bacteria a point which will soon be further ex- 

 plained. 



The conditions to which milk is subjected during 

 the separation of the cream are also far more favorable in 

 summer-time. The air in the dairy is better; the small 

 window usually found is insignificant, but it constantly 

 acts as a ventilator, being usually left open; the door is 

 also left open a large share of the day, so that a draft 

 is created. Outside the door of the dairy there is usually 

 a lawn, and dust or dirt from the surrounding regions 

 are not therefore very apt to be brought in from the 

 outside. 



Having now considered the conditions present where 

 the old shallow setting system of cream separation is prac- 

 tised, we shall consider in how far the unfavorable con- 

 ditions for the keeping quality of the products are de- 

 pendent on the method itself. 



For one thing, uncleanliness does not at all belong to 

 the method. The lack of neatness often found among 

 farmers using the system comes from their poverty and 



