. 



Xrt*' 



_CA 



l;.\( I l-.KIA IX MII.K. 



THE SOURING OF MILK IN THUNDER STORMS. 



If the souring of milk is always due to the growth of lactic 

 bacteria it becomes necessary to explain the popular belief 

 that thunder storms will sour milk. This belief rests upon a 

 mistaken interpretation of observed facts. It is certainly true 

 that milk is frequently found soured after a thunder storm, and 

 the natural interpretation has been that it is the electricity of 

 the thunder storm that produces the souring. A careful study 

 of the phenomenon has shown that this inference is incorrect. 

 It has been found that electricity, in the form of electric sparks, 

 has no power to sour milk. Such electric sparks may be dis- 

 charged indefinitely at the very surface of the milk without 

 showing the slightest ability to sour it, and the force of the 

 electricity under these conditions is certainly greater than 

 that of lightning at a distance. Electric discharges in the 

 thunder storm produce ozone and, since ozone is an active 

 oxidizing agent, it has been suggested that the ozone is the 

 cause of the souring. But this is disproved by actual experi- 

 ment, which shows that ozone, even when present in large 

 quantity, is unable to sour milk. Further, it has been found 

 that if the milk is kept properly cool the thunder storm has no 

 influence upon it. Lastly, it has been abundantly proved that 

 milk which has been deprived of its bacteria may be kept 

 indefinitely, and will remain sweet in spite of thunder storms. 

 In short, all evidence shows that the thunder storm has no 

 power of souring milk, unless bacteria are present to produce 

 the lactic acid, and that the thunder and lightning have no 

 direct effect upon the souring of milk. 



What then causes the frequent souring of milk during 

 thunder storms and the widespread belief that thunder is 

 the cause ? The answer seems to be a simple one. It is, 

 that the same agencies which produce the thunder storm 

 cause a rapid growth of bacteria. The thunder storm is 

 17 



